Biologists discover how plants evolved multiple ways to override genetic instructions

Biologists  have discovered the origin of a curious duplication that gives plants multiple ways to override instructions that are coded into their DNA. This research could help scientists exploit a plant's existing systems to favor traits that make it more resilient to environmental changes, like heat or drought stress.

This new research focuses on DNA methylation, a normal biological process in living cells wherein small chemical groups called methyl groups are added to DNA. This activity controls which genes are turned on and off, which in turn affects different traits—including how organisms respond to their environments.

Part of this job involves silencing, or turning off, certain snippets of DNA that move around within an organism's genome. These so-called jumping genes, or transposons, can cause damage if not controlled. The entire process is regulated by enzymes, but mammals and plants have developed different enzymes to add methyl groups.

Mammals only have two major enzymes that add methyl groups in one DNA context, but plants actually have multiple enzymes that do that in three DNA contexts.

The question is—why do plants need extra methylation enzymes?

Certain genes or combinations of genes are contributing to certain features or traits. If researchers find precisely how they are regulated, then they can find a way to innovate  technology for crop improvement.

Jianjun Jiang et al, Substrate specificity and protein stability drive the divergence of plant-specific DNA methyltransferases, Science Advances (2024). DOI: 10.1126/sciadv.adr2222. www.science.org/doi/10.1126/sciadv.adr2222

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Dentists are pulling 'healthy' and treatable teeth to profit from implants, experts warn

Dental implants have been used for more than half a century to surgically replace missing or damaged teeth with artificial duplicates, often with picture-perfect results. While implant dentistry was once the domain of a small group of highly trained dentists and specialists, tens of thousands of dental providers now offer the surgery and place millions of implants each year.

Amid this booming industry, some implant experts worry that many dentists are losing sight of dentistry's fundamental goal of preserving natural teeth and have become too willing to remove teeth to make room for expensive implants, according to a months-long investigation by KFF Health News and CBS News.

In interviews, 10 experts said they had each given second opinions to multiple patients who had been recommended for mouths full of implants that the experts ultimately determined were not necessary.

Separately, lawsuits filed have alleged that implant patients  have experienced painful complications that have required corrective surgery, while other lawsuits alleged dentists at some implant clinics have persuaded, pressured, or forced patients to remove teeth unnecessarily.

The experts warn that implants, for a single tooth or an entire mouth, expose patients to costs and surgery complications, plus a new risk of future dental problems with fewer treatment options because their natural teeth are forever gone.

There are many cases where teeth're perfectly fine, and they're being removed unnecessarily.

2024 KFF Health News. Distributed by Tribune Content Agency, LLC.

https://medicalxpress.com/news/2024-11-dentists-healthy-treatable-t...

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Drowsy driving: Not taken as seriously as drunk driving, but it can kill

Some time back my brother-in-law who did two back to back night shifts, actually they 're 48 hour nonstop work shifts, at Airport (he 's  Airport manager for his International  airlines) was driving his car and told us temporarily felt drowsy and hit a person on the road. Luckily the person just fell down with and had just two light bruises but demanded money and my brother in law had to part with Rs.10000 as compensation. From then onwards he has been refusing to work continuously for more than 24 hours. 

Folks are more likely to drive drowsy than drive drunk, even though both raise the risk of a fatal crash, a new survey now shows confirming his fears.

About four in 10 adults say they'll find alternative transportation when they haven't gotten enough sleep, according to a poll conducted online.

By comparison, nearly seven in 10 adults say they won't drive after having a few drinks.

Drowsy driving is a significant threat to road safety, just like drunk, drugged or distracted driving can be, according to scientific studies.

Researchers want the public to know that sleeping only three to four hours before driving is like having a few drinks, and encourage everyone to have a backup plan in place for when they are not alert enough to drive safely, like choosing ride share or taxi options, or calling friends and family to help you and others stay safe.

Drowsy driving is responsible for one in every five deadly motor vehicle crashes, and one of every 10 crashes that result in hospitalization, according to the AAA Foundation for Traffic Safety.

A survey also found that:

• Only half of adults are likely to delay or change plans to avoid driving drowsy, compared to more than eight in 10 following a few drinks
• Just 50% are likely to avoid driving when they haven't gotten enough sleep, compared to almost 90% who've had a few drinks
• More people have urged someone else not to drive because of drinking than for being too tired

Being awake and alert in the driver's seat is as important as not being under the influence, so don't hesitate to change your plans when you shouldn't drive.

To avoid drowsy driving, the NSF recommends that people:

• Get seven to nine hours of sleep
• Plan long trips with a companion who can help a driver stay alert and take the wheel when necessary
• Schedule regular stops every 100 miles or two hours
• Be mindful of warning signs like frequent blinking, yawning or having difficulty with lane and speed control

Source: https://www.nhtsa.gov/risky-driving/drowsy-driving

'Potential misdiagnosis is just a click away': Researchers find design flaws and oversight issues in certain health apps

AI-powered apps offering medical diagnoses at the click of a button are often limited by biased data and a lack of regulation, leading to inaccurate and unsafe health advice, a new study found.

 Researchers presented symptom data from known medical cases to two popular, representative apps to see how well they diagnosed the conditions. While the apps sometimes gave correct diagnoses, they often failed to detect serious conditions, according to findings published in the Journal of Medical Internet Research. This potentially resulted in delayed treatment.

The researchers identified two main issues with the health apps they studied: biased data and a lack of regulation.

The bias issue is known as the "garbage in, garbage out" problem.

These apps often learn from skewed datasets that don't accurately reflect diverse populations.

Because the apps rely on data from smartphone users, they tend to exclude lower-income individuals. Race and ethnicity are also underrepresented in the data, said the authors. This creates a cycle where an app's assessments are based on a narrower group of users, leading to more biased results and potentially inaccurate medical advice.

While apps often include disclaimers stating they do not provide medical advice, the scholar argues that users' interpretations of these disclaimers—if read—do not always align.

The second issue is the "black box" nature of AI systems, where the technology evolves with minimal human oversight. Researchers say lack of transparency means even an app's developers may not fully understand how it reaches conclusions.

Without clear regulations, developers aren't held accountable, making doctors reluctant to recommend these tools. For users, this means a potential misdiagnosis is just a click away.

Ma'n H Zawati et al, Does an App a Day Keep the Doctor Away? AI Symptom Checker Applications, Entrenched Bias, and Professional Responsibility, Journal of Medical Internet Research (2024). DOI: 10.2196/50344

Fecal transplants may involve more than bacterial transfer, study suggests

In a novel study that identified male chromosome genetic material in the intestines of female patients undergoing fecal transplants, researchers  say they have significantly expanded scientific understanding of how some of these transplants may succeed and work.

Fecal microbiota transplant, or FMT, is a procedure in which stool from healthy donors is transplanted via colonoscopy into the bowels of people with dangerous and recurrent infections caused by a bacterium called Clostridioides difficile (C. difficile). Many previous studies show that the transplanted fecal material from healthy donors restores the balance of good bacteria that are markers of a healthy gut in people whose recurrent C.difficile infections have been treated with heavy duty antibiotics that wipe out "good" bacteria as well as bad.

Recurrent C. difficile infection is an often debilitating condition marked by severe diarrhea and inflammation of the colon. Researchers say the infections are notoriously difficult to treat, with conventional antibiotic therapies often failing to provide long-term relief and cure of the infection.

The new study, described in the journal Gastro Hep Advances on October 18, shows that transfer donor cells that line the intestinal tract along with the donor's fecal matter may be responsible for improved outcomes for at least some patients.

This study suggests the possibility of donor intestinal epithelial cell transfer during fecal microbiota transplant, rather than the mere transfer of bacteria from donor fecal samples, can be more effective.

Donor intestinal epithelial cells live in the inner lining of the colon and the small intestine. These cells maintain the intestine's structural integrity and functional capacity. Humans shed millions of these cells into the fecal stream every day. In the new study, the researchers found that the SRY gene responsible for the male-defining characteristics of Y chromosomes, along with evidence of the Y chromosome itself, was detected in the fecal samples of some female patients receiving FMT from male donors.

The long-term detection of the Y chromosome suggests that, in addition to the intestinal microbiota restoration, FMT may facilitate epithelial repair in the gut lining resulting in the altered milieu of the intestinal ecosystem. These observations open up a deeper understanding of the mechanism by which FMT works.

This research points to a much more complex interaction between the donor microbiome and the recipient's gut environment than previously reported.

This finding suggests that stool is a much more complex excretion than we thought it was.

However, more studies are needed in a larger group of female patients who receive FMT from healthy male donors to determine the extent of epithelial "engraftment" in the intestines of FMT patients.

Sudhir K. Dutta et al, Detection of human Y chromosome and SRY gene in fecal samples of female patients following fecal microbiota transplantation, Gastro Hep Advances (2024). DOI: 10.1016/j.gastha.2024.10.008

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Research in Thailand supports stool DNA as non-invasive alternative for colorectal cancer screening

A recent prospective cross-sectional study  demonstrates that multitarget stool DNA testing is highly sensitive and specific for detecting colorectal cancer (CRC) among  individuals. Researchers  think that this testing method could serve as a viable non-invasive alternative to colonoscopy, especially in settings where colonoscopy is less accessible or less accepted by patients.

Researchers focused on evaluating the diagnostic performance of the multitarget stool DNA testing for detecting CRC and advanced adenoma, using colonoscopy as the reference standard. The study included both asymptomatic and symptomatic patients who underwent stool DNA testing followed by colonoscopy. The multitarget stool DNA test targeted methylation statuses of SDC2, ADHFE1, and PPP2R5C genes. Sensitivity, specificity, and other diagnostic parameters were analyzed.

In the study, data from 274 patients (mean age 62 years, with a predominantly female cohort at 60.6%) was evaluated. Colorectal cancer was identified in 17.2% of participants, while 6.2% were found to have advanced adenomas, which are precursors to cancer.

The multitarget stool DNA test, a non-invasive screening method, yielded impressive results: it detected CRC with a sensitivity of 91.5% and a specificity of 90.3%, accurately identifying cancer in over 90% of cases. The test's sensitivity was consistent across both right-sided and left-sided colon lesions, at 92.3% and 91.2%, respectively.

For advanced colorectal neoplasms, which include both CRC and advanced adenomas, the test demonstrated a sensitivity of 75% and a specificity of 91.9%, marking it as a promising tool for the early detection of serious colorectal conditions. These findings highlight the test's potential as an effective screening option for detecting CRC, especially for larger lesions, although some limitations remain for detecting smaller-sized abnormalities.

BGI Genomics' COLOTECT stool DNA testing kits were used for sample and raw data collection. COLOTECT is a non-invasive tool for early colorectal cancer detection based on DNA methylation testing, targeting the methylation profile of colorectal exfoliated cells to assess the risk of colorectal cancer and advanced adenomas.

This tool requires no special equipment, imposes no dietary restrictions, and is entirely non-invasive. In recent years, DNA methylation-based colorectal cancer detection has gained recognition, being incorporated into multiple CRC screening guidelines and expert consensus worldwide.

Varut Lohsiriwat et al, Diagnostic Accuracy of Multitarget Stool DNA Test for Colorectal Cancer Screening and Detecting in Thailand, Asian Pacific Journal of Cancer Prevention (2024). DOI: 10.31557/APJCP.2024.25.10.3661

Neuroimmune communication pathway reveals interactions that may drive endometriosis-associated pain

Researchers have discovered a neuroimmune communication pathway that may drive endometriosis-associated pain and lesion growth.

Endometriosis is a debilitating inflammatory disease affecting up to 15% of women and is characterized by the growth of endometrial-like tissue outside the uterus. Treatments can currently only target symptoms, with over-the-counter pain medicines and hormonal birth control, or in some cases, surgery.

Endometriosis occurs when cell tissues normally found within the uterus lining take root in areas outside the uterus. This tissue is hormonally sensitive and can become inflamed, especially during menstrual cycles, and can cause severe cramping, pain, and other symptoms depending on the area affected.

Because of the abnormal location, the endometrial-like tissues do not vacate during menstruation as similar cells within the lining do. Instead, they can form scar tissues, cysts, lesions, nodules, and connective tissues that can bind to other organs.

In a study, "Nociceptor-to-macrophage communication through CGRP/RAMP1 signaling drives endometriosis-associated pain and lesion growth inmice," published in Science Translational Medicine, the research teams focused on the gene-related peptide (CGRP) and its receptor peptide RAMP1 revealed the nociceptor-to-macrophage communication pathway.

Using samples from eight patients with endometriosis and a mouse model of the disease, the researchers found that both human and mouse endometriosis lesions contain CGRP and its coreceptor RAMP1.

In mice, the team reduced the activity of nociceptors (nerve cells responsible for sensing pain) by employing genetic techniques and chemical treatments. They bred mice to lack specific nociceptor cells and used compounds like resiniferatoxin to deactivate these nerves chemically. This led to decreased pain behaviours and smaller lesion sizes, suggesting that active nociceptors contribute to disease progression.

Victor Fattori et al, Nociceptor-to-macrophage communication through CGRP/RAMP1 signaling drives endometriosis-associated pain and lesion growth in mice, Science Translational Medicine (2024). DOI: 10.1126/scitranslmed.adk8230

Large-scale study uncovers genetic factors associated with disk herniations

Lumbar disk herniation is one of the most common structural changes in the lower back and the most common cause of radiating pain, or sciatica, in the leg. Hereditary risk factors for disk herniations were investigated in an international study utilizing data from FinnGen, the Estonian Biobank, and the UK Biobank. The study, published in Nature Communications on 7 November, analyzed the genetic and health data of 829,699 participants.

The study found 41 novel regions of the genome that modify the disease risk for disk herniations, in addition to the previously identified 23 regions. In the study, numerous genomic regions potentially affecting the structure of the disks and inflammatory factors were found.

In addition to these, the study identified new associations near genes related to the nervous system and nerve function. Findings related to the functioning of the nervous system have increased our understanding of the connection between symptomatic disk herniations and radiating pain.

The study also analyzed disk herniation patients who required surgical treatment. A total of five novel genomic regions were found to be associated with the more severe disk herniations which require surgery.

Genome-wide meta-analysis conducted in three large biobanks expands the genetic landscape of lumbar disc herniations., Nature Communications (2024). DOI: 10.1038/s41467-024-53467-z , www.nature.com/articles/s41467-024-53467-z

Defense or growth: Study finds trade-off in how plants allocate resources

The more a plant species invests in defense, the less potential it has for growth, according to a new study. Research made possible by open science provides new insights into plant adaptation and interspecies variation.

Pathogens can significantly weaken the fitness of their hosts, sometimes even causing host mortality. Yet considerable variation is found between species in their investment in disease defense. Evolutionary theory predicts that allocation costs regulate this investment, but testing this hypothesis has been challenging.
In a study published in Science, researchers used open databases to identify plant defense genes and growth traits in 184 plant species.

They found striking variation among plant species in the number of defense genes, which ranged from 44 to 2,256. Examples include asparagus, which has only 72 resistance genes, while one chili variety has as many as 1,095.

They also discovered a negative correlation between defense investment and growth traits in wild plants: the higher the proportion of a plant's genome is dedicated to defense genes, the lower growth potential it has.

The study demonstrates the significant role of allocation costs in the generation and maintenance of biodiversity. The findings also shed light on mechanisms that limit the evolution of defense.

Allocation costs refer to the trade-off in distributing resources among different life functions. For plants, this means that if a plant uses many resources (like energy and nutrients) to maintain its defenses, this may detract from other functions such as growth. In other words, the plant must balance its resource use, which can lead to a scenario where a strong defense reduces growth potential, or vice versa.

The study also examined cultivated plants that have been bred for specific traits. In these plants, a negative correlation between growth and defense was not observed due to the breeding that reduced natural variation in the genomes of crop plants.

Michael Giolai et al, A trade-off between investment in molecular defence repertoires and growth in plants, Science (2024). DOI: 10.1126/science.adn2779. www.science.org/doi/10.1126/science.adn2779

Researchers discover genetic reason for the red, yellow and orange bills of Australian finches

What gives an Australian finch its brilliantly colored red, yellow or orange bill? A major new study has uncovered the genetic switches controlling these distinctive colors, revealing a key piece in the puzzle of how animals develop their colouration.

The research published in Current Biology, reveals how yellow and red bill colors evolved in the long-tailed finch through changes in just a few key genes that control how birds process yellow pigments from their diet.

The study focused on two subspecies of the long-tailed finch found across northern Australia—one with a yellow bill based in the Kimberley region of Western Australia, and the other with a red bill from the Northern Territory. Where these subspecies meet, they produce hybrid offspring with orange bills.

Most long-tailed finches in Australia today have bright red bills, with the color coming from carotenoid (yellow) pigments in the seeds they eat. The birds produce enzymes that chemically turn the yellow pigments from their diet into red pigments, which are deposited in their growing bills.

By analyzing the DNA of more than 900 finches, the researchers identified the exact genetic changes responsible for the different bill colors. They discovered that yellow-billed finches have genetic variations that prevent them from converting yellow dietary pigments into red ones.

When red-billed and yellow-billed finches mate, their offspring have orange bills. By studying the exact shade of orange in these hybrid birds, researchers could identify the different genes controlling bill colour.

This discovery helps us understand how animals can evolve different color signals, contributing to the amazing colors of nature.

There's another fascinating twist to the story. Birds use carotenoid pigments for decorative feather, skin and bill colors—but also for vision. These pigments are used in the retinas of their eyes, where tiny oil droplets containing carotenoids help filter light and enable colour vision.

This led to a key discovery. While yellow-billed finches don't produce red carotenoids in their bills, they can still make them in their retinas.

It's not that yellow-billed birds lack the genes for making red colouring; rather, they control these genes differently in different parts of their bodies.

The research team found evidence buried deep in the genome—the complete DNA code for the different forms—that the yellow bill color, which first appeared about 100,000 years ago, provided some evolutionary advantage, allowing the genes for yellow bills to spread into populations of red-billed finches.

While red-colored bills were the ancestral state for these finches, we can see natural selection has favored the yellow coloration as these populations have mixed.

Part 1

This tells us that having a yellow bill rather than a red one provided some benefit to these birds over many generations."

The study provides new insights into how animal coloration evolves and may help explain similar color variations seen in other bird species around the world.

Daniel M. Hooper et al, Spread of yellow-bill-color alleles favored by selection in the long-tailed finch hybrid system, Current Biology (2024). DOI: 10.1016/j.cub.2024.10.019

Part 2

 Plate tectonics research provide a new view of deep Earth's carbon emissions

From time to time, when Earth's tectonic plates shift, the planet emits a long, slow belch of carbon dioxide. In a new modeling study published in Geochemistry, Geophysics, Geosystems, researchers show how this gas released from deep Earth may have affected the climate over the past billion years.

Volcanoes, undersea vents, and mid-ocean ridges are all found where Earth's plates collide or separate. Each of these structures gives carbon dioxide a route to escape from the depths of the planet and enter the atmosphere. Although their impact on the climate is minor compared to anthropogenic emissions, gases released from deep Earth are thought to have a substantial impact on the composition of Earth's atmosphere over geologic timescales.

Scientists have often estimated the volume of such carbon emissions solely on the basis of the gas released by plate tectonics. But plate tectonics can also capture carbon by incorporating it into new crust formed at mid-ocean ridges. In the new work, researchers drew on two recent studies about the past billion years of plate movement to more precisely model how much carbon dioxide this process has generated.

The model's findings are consistent with how Earth's climate is thought to have changed over time. For example, the periods during which the model suggests more carbon was being released line up with warmer periods of Earth's history, such as the start of the Ediacaran period about 653 million years ago.

Periods that the model suggests may have had lower levels of carbon outgassing coincide with colder periods of Earth's history, such as the "snowball Earth" period from 700 million to 600 million years ago.

The research also suggests that Pangea's breakup allowed large amounts of carbon dioxide to be released as the planet's plates moved apart, which is consistent with the warming that's thought to have occurred during that time.

Tectonic activity is a major determinant of Earth's atmospheric composition over geologic time, the researchers conclude.

R. Dietmar Müller et al, Solid Earth Carbon Degassing and Sequestration Since 1 Billion Years Ago, Geochemistry, Geophysics, Geosystems (2024). DOI: 10.1029/2024GC011713

Elephant turns a hose into sophisticated showering tool

Tool use isn't unique to humans. Chimpanzees use sticks as tools. Dolphins, crows, and elephants are known for their tool-use abilities, too. Now a report in Current Biology on November 8, 2024, highlights elephants' remarkable skill in using a hose as a flexible shower head. As an unexpected bonus, researchers say they also have evidence that a fellow elephant knows how to turn the water off, perhaps as a kind of "prank."

 Water hose tool use and showering behavior by Asian elephants, Current Biology (2024). DOI: 10.1016/j.cub.2024.10.017. www.cell.com/current-biology/f … 0960-9822(24)01371-X

Memories are not only in the brain, human cell study finds

It's common knowledge that our brains—and, specifically, our brain cells—store memories. But a team of scientists has discovered that cells from other parts of the body also perform a memory function, opening new pathways for understanding how memory works and creating the potential to enhance learning and to treat memory-related afflictions.

Learning and memory are generally associated with brains and brain cells alone, but this new study shows that other cells in the body can learn and form memories, too.

The research sought to better understand if non-brain cells help with memory by borrowing from a long-established neurological property—the massed-spaced effect—which shows that we tend to retain information better when studied in spaced intervals rather than in a single, intensive session—better known as cramming for a test.

In the research, the scientists replicated learning over time by studying two types of non-brain human cells in a laboratory (one from nerve tissue and one from kidney tissue) and exposing them to different patterns of chemical signals—just like brain cells are exposed to patterns of neurotransmitters when we learn new information.

In response, the non-brain cells turned on a "memory gene"—the same gene that brain cells turn on when they detect a pattern in the information and restructure their connections in order to form memories.

To monitor the memory and learning process, the scientists engineered these non-brain cells to make a glowing protein, which indicated when the memory gene was on and when it was off.

The results showed that these cells could determine when the chemical pulses, which imitated bursts of neurotransmitter in the brain, were repeated rather than simply prolonged—just as neurons in our brain can register when we learn with breaks rather than cramming all the material in one sitting.

Specifically, when the pulses were delivered in spaced-out intervals, they turned on the "memory gene" more strongly, and for a longer time, than when the same treatment was delivered all at once.

This reflects the massed-space effect in action. 

It shows that the ability to learn from spaced repetition isn't unique to brain cells, but, in fact, might be a fundamental property of all cells.

The researchers add that the findings not only offer new ways to study memory, but also point to potential health-related gains.

This discovery opens new doors for understanding how memory works and could lead to better ways to enhance learning and treat memory problems.

At the same time, it suggests that in the future, we will need to treat our body more like the brain—for example, consider what our pancreas remembers about the pattern of our past meals to maintain healthy levels of blood glucose or consider what a cancer cell remembers about the pattern of chemotherapy.

N. V. Kukushkin et al, The massed-spaced learning effect in non-neural human cells, Nature Communications (2024). DOI: 10.1038/s41467-024-53922-x

Biomolecular Condensates

I Made Kidney Stones So I Could DESTROY THEM FOREVER

Stem-cell transplants restore lost vision

Three people with severely impaired vision have had their sight substantially improved by a stem-cell transplant. These improvements have now lasted more than a year. A fourth person also experienced a boost in their vision, but it did not last. The four are the first to receive a transplant of reprogrammed stem cells to treat damaged corneas, the transparent outer surface of the eye. The team behind the treatment will launch larger clinical trials next year.

Nature | 
Reference: The Lancet paper

Researchers demonstrate universal control of a quantum dot-based system with four singlet-triplet qubits

Being able to precisely manipulate interacting spins in quantum systems is of key importance for the development of reliable and highly performing quantum computers. This has proven to be particularly challenging for nanoscale systems with many spins that are based on quantum dots (i.e., tiny semiconductor devices).

Researchers recently demonstrated the universal control of a quantum dot-based system with four singlet-triplet qubits. Their paper, published in Nature Nanotechnology, could open new possibilities for the successful upscaling of quantum information processing systems.

Xin Zhang et al, Universal control of four singlet–triplet qubits, Nature Nanotechnology (2024). DOI: 10.1038/s41565-024-01817-9

A formula for life? New model calculates chances of intelligent beings in our universe and beyond

The chances of intelligent life emerging in our universe—and in any hypothetical ones beyond it—can be estimated by a new theoretical model which has echoes of the famous Drake Equation.

This was the formula that American astronomer Dr. Frank Drake came up with in the 1960s to calculate the number of detectable extraterrestrial civilizations in our Milky Way galaxy.

More than 60 years on, astrophysicists led by Durham University have produced a different model which instead focuses on the conditions created by the acceleration of the universe's expansion and the amount of stars formed.

It is thought this expansion is being driven by a mysterious force called dark energy that makes up more than two thirds of the universe.

Since stars are a precondition for the emergence of life as we know it, the model could therefore be used to estimate the probability of generating intelligent life in our universe, and in a multiverse scenario of different hypothetical universes.

The new research does not attempt to calculate the absolute number of observers (i.e. intelligent life) in the universe but instead considers the relative probability of a randomly chosen observer inhabiting a universe with particular properties. The study has been published in Monthly Notices of the Royal Astronomical Society.

Part 1

It concludes that a typical observer would expect to experience a substantially larger density of dark energy than is seen in our own universe—suggesting the ingredients it possesses make it a rare and unusual case in the multiverse.

The approach presented in the paper involves calculating the fraction of ordinary matter converted into stars over the entire history of the universe, for different dark energy densities.

The model predicts this fraction would be approximately 27% in a universe that is most efficient at forming stars, compared to 23% in our own universe.

This means we don't live in the hypothetical universe with the highest odds of forming intelligent life forms. Or in other words, the value of dark energy density we observe in our universe is not the one that would maximize the chances of life, according to the model.
Understanding dark energy and the impact on our universe is one of the biggest challenges in cosmology and fundamental physics.

The parameters that govern our universe, including the density of dark energy, could explain our own existence.
Surprisingly, though, researchers found that even a significantly higher dark energy density would still be compatible with life, suggesting we may not live in the most likely of universes.
The new model could allow scientists to understand the effects of differing densities of dark energy on the formation of structures in the universe and the conditions for life to develop in the cosmos.

Dark energy makes the universe expand faster, balancing gravity's pull and creating a universe where both expansion and structure formation are possible.

However, for life to develop, there would need to be regions where matter can clump together to form stars and planets, and it would need to remain stable for billions of years to allow life to evolve.
Crucially, the research suggests that the astrophysics of star formation and the evolution of the large-scale structure of the universe combine in a subtle way to determine the optimal value of the dark energy density needed for the generation of intelligent life.
Part 2

Dr. Drake's equation was more of a guide for scientists on how to go about searching for life, rather than an estimating tool or serious attempt to determine an accurate result.

Its parameters included the rate of yearly star formation in the Milky Way, the fraction of stars with planets orbiting them and the number of worlds that could potentially support life.

By comparison, the new model connects the rate of yearly star formation in the universe with its fundamental ingredients, such as the aforementioned dark energy density.

 Daniele Sorini et al, The impact of the cosmological constant on past and future star formation, Monthly Notices of the Royal Astronomical Society (2024). DOI: 10.1093/mnras/stae2236. academic.oup.com/mnras/article … .1093/mnras/stae2236

Part 3

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Experiment supports existence of a new type of superconductor

A research team has found the strongest evidence yet of a novel type of superconducting material, a fundamental science breakthrough that may open the door to coaxing superconductivity—the flow of electric current without a loss of energy—in a new way.

The discovery also lends tangible support to a long-held theory about superconductivity—that it could be based upon electronic nematicity, a phase of matter in which particles break their rotational symmetry.

Here is what that means. In iron selenide crystals mixed with sulfur, iron atoms are positioned in a grid. At room temperature, an electron in an iron atom cannot distinguish between horizontal and vertical directions. But at lower temperatures, the electron may enter a "nematic" phase, where it begins to prefer moving in one direction or the other.

In some instances, the electron may start to fluctuate between preferring one direction, then the other. This is called nematic fluctuation.

For decades, physicists have attempted to prove the existence of superconductivity due to nematic fluctuations, with little success. But the new study, a multi-institutional effort led by Yale's Eduardo H. da Silva Neto, offers promise.

The findings appear in the journal Nature Physics.

Pranab Kumar Nag et al, Highly anisotropic superconducting gap near the nematic quantum critical point of FeSe1−xSx, Nature Physics (2024). DOI: 10.1038/s41567-024-02683-x

Indicators of an aging brain

Researchers, working with the Biomarkers for Older Controls at Risk for Dementia (BIOCARD) cohort, have found that certain factors are linked to faster brain shrinkage and quicker progression from normal thinking abilities to mild cognitive impairment (MCI). People with type 2 diabetes and low levels of specific proteins in their cerebrospinal fluid showed more rapid brain changes and developed MCI sooner than others.

Long-term studies tracking brain changes over many years are rare but valuable. Previous research mostly provided snapshots in time, which can't show how individual brains change over the years. By following participants for up to 27 years (20-year median), this study offers new insights into how health conditions might speed up brain aging.

In a study, "Acceleration of Brain Atrophy and Progression From Normal Cognition to Mild Cognitive Impairment," published in JAMA Network Open, researchers used the BIOCARD cohort to examine risk factors associated with the acceleration of brain atrophy and progression from normal cognition to MCI. An Invited Commentary is also available.

 A total of 185 participants, averaging 55 years old at the start and all cognitively normal, were selected. They underwent brain scans and tests of their cerebrospinal fluid over 20 years, measuring changes in brain structures and levels of proteins associated with Alzheimer's disease.

Findings showed that high rates of white matter shrinkage and enlargement of the brain's ventricles (fluid-filled spaces) were significant predictors of earlier MCI onset. Specifically, white matter atrophy was associated with an 86% higher risk and ventricular enlargement with a 71% higher risk of progressing to MCI.

Individuals with diabetes showed an average 41% higher risk of progressing from normal cognition to MCI compared to individuals without.
A low ratio of amyloid β peptides Aβ42 to Aβ40 in cerebrospinal fluid was associated with a 48% higher risk of developing MCI. This ratio acts as a biomarker for Alzheimer's disease, where an imbalance between these two forms of amyloid beta proteins is linked to the formation of harmful plaques in the brain.

When participants had both diabetes and a low Aβ42 to Aβ40 ratio, their risk of progressing to MCI increased by 55%, demonstrating that these two factors together significantly heighten the likelihood of cognitive decline.

Part 1

These results support the importance of early identification of individuals exhibiting accelerated brain atrophy and certain unfavorable biomarkers. By recognizing when higher risk is present, preventive intervention strategies can be optimized to delay or hopefully even prevent the onset of MCI.

Yuto Uchida et al, Acceleration of Brain Atrophy and Progression From Normal Cognition to Mild Cognitive Impairment, JAMA Network Open (2024). DOI: 10.1001/jamanetworkopen.2024.41505

 Shohei Fujita, Optimizing Strategies to Prevent Cognitive Decline With 20-Year Brain Imaging, JAMA Network Open (2024). DOI: 10.1001/jamanetworkopen.2024.41466

Part 2

Toxic smog smothering India's capital smashes WHO limit

Residents of India's capital New Delhi choked in a blanketing toxic smog this week as worsening air pollution surged past 50 times the World Health Organization's recommended daily maximum.

Many in the city cannot afford air filters, nor do they have homes they can effectively seal from the misery of foul smelling air blamed for thousands of premature deaths.

Cooler temperatures and slow-moving winds trap deadly pollutants each winter, stretching from mid-October until at least January.

At dawn on Wednesday, "hazardous" pollutant levels in parts of the sprawling urban area of more than 30 million people topped 806 micrograms per cubic meter, according to monitoring firm IQAir.

That is more than 53 times the World Health Organization recommended daily maximum of fine particulate matter—dangerous cancer-causing microparticles known as PM2.5 pollutants that enter the bloodstream through the lungs.

By midday, when air usually is at its best, it eased to about 25-35 times above danger levels, depending on different districts.

Now breathing in Delhi has become  like "smoking cigarettes". Older people have difficulties breathing. It is particularly punishing for babies, children and the elderly.

The city is blanketed in acrid smog each year, primarily blamed on stubble burning by farmers in neighboring regions to clear their fields for plowing, as well as factories, Diwali fire works and traffic fumes.

But a report by The New York Times this month, based on air and soil samples it collected over five years, revealed the dangerous fumes also spewing from a power plant incinerating the city's landfill garbage mountains.

Experts the newspaper spoke to said that the levels of heavy metals found were "alarming".

Swirling white clouds of smog also delayed several flights across northern India.

The India Meteorological Department said that at least 18 regional airports had a visibility lower than 1,000 meters (1,093 yards)—dropping below 500 meters in Delhi.

India's Supreme Court last month ruled that clean air was a fundamental human right, ordering both the central government and state-level authorities to take action.

But politicians are accused of not wanting to anger key figures in their constituencies, particularly powerful farming groups and industrialists.

City authorities have launched some initiatives to tackle pollution, which have done little in practice.

The choking carbon smog across Delhi came as researchers warned that planet-warming fossil fuel emissions would hit a record high this year, according to new findings from an international network of scientists at the Global Carbon Project.

Researchers said increases in CO₂ emissions from India—as well as growth in international aviation—drove emissions up.

It found no sign the world was moving away from fossil fuels as planned.

Source: News agencies

We need to talk about what smartphones are doing to kids' brains, say experts

We know there are links between young people overusing devices and a decline in cognitive abilities, as well as problems with attention, focus and memory.

Researchers  recently published a review and meta-analysis of 34 studies looking at neuropsychological deficits in children and teenagers who had screen-use disorders—basically what can be classified as screen addictions.

Their findings showed strong evidence of impacts on attention, focus and executive functioning in these young people, but also changes in their brains that were visible on scans, with the loss of gray and white matter in areas of the frontal lobe that are associated with learning and memory.

Yes, you read that correctly.

Overuse can result in young people losing brain capacity.

These studies relate to the roughly 3% of teenagers who are classified as having a clinical screen overuse disorder, but the latest figures show the average Australian teenager is spending four to six hours a day on social media, and a total of up to eight hours a day using screens for leisure.

Recent research from the University of North Carolina shows brain changes related to habitual checking of social media in Grade 6 and 7 students over three years. A third of the children—those who were frequently checking their feeds—showed significant changes in brain areas involved in emotion, motivation and cognition.

Brains are very much a use-it-or-lose-it organ: if you challenge yourself through thinking, problem-solving and learning, you develop new connections in your brain. If you don't challenge yourself, not only do new connections not form, but the old ones start to die off.

Dementia might be thought of as an old person's disease, but younger people can also be affected. Early onset dementia usually affects adults aged between 30 and 65, but there are rare cases of people being diagnosed in their 20s. In the past, the majority of cases of younger-onset dementia were believed to be inherited.

Part 1

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

**

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

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

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

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

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

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

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

Environmental health of waste explained in 101 seconds 

Scientists propose drug-free method to combat antibiotic-resistant bacteria

Recent estimates indicate that deadly antibiotic-resistant infections will rapidly escalate over the next quarter century. More than 1 million people died from drug-resistant infections each year from 1990 to 2021, a recent study reported, with new projections surging to nearly 2 million deaths each year by 2050.

In an effort to counteract this public health crisis, scientists are looking for new solutions inside the intricate mechanics of bacterial infection. A study by researchers  has discovered a vulnerability within strains of bacteria that are antibiotic resistant. They  investigated the antibiotic resistance of the bacterium Bacillus subtilis.

Their research was motivated by the question of why mutant variants of bacteria do not proliferate and take over the population once they have developed an antibiotic-resistant advantage. With an upper hand over other bacteria lacking similar antibiotic resistance, such bacteria should become dominant. Yet they are not. Why?

The answer, reported in the journal Science Advances, is that antibiotic resistance comes at a cost. While antibiotic resistance provides some advantages for the bacteria to survive, the team discovered that it's also linked with a physiological limitation that hinders potential dominance.

This fact, the researchers note, potentially could be exploited to stop the spread of antibiotic resistance.

The researchers discovered an Achilles heel of antibiotic resistant bacteria. They can now  take advantage of this cost to suppress the establishment of antibiotic resistance without drugs or harmful chemicals.

Part 1

Spontaneous mutations of DNA arise in all living cells, including those within bacteria. Some of these mutations lead to antibiotic resistance. Researchers focused on physiological mechanisms related to ribosomes, the micro machines within cells that play a key role in synthesizing proteins and translating genetic codes.
All cells rely on charged ions such as magnesium ions to survive. Ribosomes are dependent upon magnesium ions since this metal cation helps stabilize their structure and function.

However, atomic-scale modeling during the new research found that mutant ribosome variants that bestow antibiotic resistance excessively compete for magnesium ions with adenosine triphosphate (ATP) molecules, which provide energy to drive living cells. Mathematical models further showed that this results in a ribosome versus ATP tug-of-war over a limited supply of magnesium in the cell.
Studying a ribosome variant within Bacillus subtilis called "L22," the researchers found that competition for magnesium hinders the growth of L22 more than a normal "wild type" ribosome that is not resistant to antibiotics. Hence, the competition levies a physiological toll linked to mutant bacteria with resistance.
This newly discovered weakness can now be used as a target to counteract antibiotic resistance without the use of drugs or toxic chemicals. For example, it may be possible to chelate magnesium ions from bacterial environments, which should selectively inhibit resistant strains without impacting the wild type bacteria that may be beneficial to our health.

Eun Chae Moon et al, Physiological cost of antibiotic resistance: Insights from a ribosome variant in bacteria, Science Advances (2024). DOI: 10.1126/sciadv.adq5249. www.science.org/doi/10.1126/sciadv.adq5249

Part 2

Scientists discover laser light can cast a shadow

Can light itself cast a shadow? Researchers have found that under certain conditions, a laser beam can act like an opaque object and cast a shadow. The discovery challenges the traditional understanding of shadows and opens new possibilities for technologies that could use a laser beam to control another laser beam.

Laser light casting a shadow was previously thought impossible since light usually passes through other light without interacting. This new demonstration of a very counter-intuitive optical effect invites us to reconsider our notion of shadow.

In Optica, researchers describe how they used a ruby crystal and specific laser wavelengths to show that a laser beam could block light and create a visible shadow due to a nonlinear optical process. This effect occurs when light interacts with a material in an intensity-dependent way and can influence another optical field.

The new research is part of a larger exploration into how a light beam interacts with another light beam under special conditions and nonlinear optical processes.

 The researchers directed a high-power green laser through a cube made of standard ruby crystal and illuminated it with a blue laser from the side. When the green laser enters the ruby, it locally changes the material response to the blue wavelength. The green laser acts like an ordinary object while the blue laser acts like illumination.

The interaction between the two light sources created a shadow on a screen that was visible as a dark area where the green laser blocked the blue light. It met all the criteria for a shadow because it was visible to the naked eye, followed the contours of the surface it fell on and followed the position and shape of the laser beam, which acted as an object.

The laser shadow effect is a consequence of optical nonlinear absorption in the ruby. The effect occurs because the green laser increases the optical absorption of the blue illuminating laser beam, creating a matching region in the illuminating light with lower optical intensity. The result is a darker area that appears as a shadow of the green laser beam.

This discovery expands our understanding of light-matter interactions and opens up new possibilities for utilizing light in ways we hadn't considered before.

The researchers experimentally measured the dependence of the shadow's contrast on the laser beam's power, finding a maximum contrast of approximately 22%, similar to the contrast of a tree's shadow on a sunny day. They also developed a theoretical model and showed that it could accurately predict the shadow contrast.

 Raphael Abrahao et al, The shadow of a laser beam, Optica (2024). DOI: 10.1364/OPTICA.534596

Altering two genes to produce sweeter tomatoes without sacrificing size, weight or yield

A team of horticulturists, bio-breeders and agriculture specialists affiliated with a host of institutions across China has produced sweeter tomatoes without sacrificing size, weight or yield by altering two of their genes. In their study, published in the journal Nature, the group modified the genes of a tomato variant that coded for proteins that lowered levels of enzymes related to sugar production.

Over the past several centuries, farmers around the world have crossbred tomato plants with the aim of improving yields and increasing fruit size. The result has been a massive growth in both. Unfortunately, making tomatoes bigger has also made them less sweet. Past efforts to make large modern tomatoes sweeter have resulted in smaller yields.
For this new study, the research team took a new approach. They began by looking into the reason for the loss of sweetness in tomatoes and partially corrected crossbreeding effects on the tomato genome.

The research team discovered two genes in multiple tomato variants that were more active in larger varieties. Called SlCDPK26 and SlCDPK27, the two genes were found to code for proteins that lowered the levels of enzymes that produce sugar. The researchers next genetically modified the genome of a variety of large tomato called Money Maker to disable the two genes they had identified.

Plants grown with the modification produced tomatoes with a 30% increase in fructose and glucose levels with no reduction in size or weight. The team further confirmed that the tomatoes were sweeter by tasting them. The gene alterations did not diminish yields—the only other difference they found was that the tomatoes produced fewer seeds, which were also smaller. They suggest consumers would probably like this added feature.

Jinzhe Zhang et al, Releasing a sugar brake generates sweeter tomato without yield penalty, Nature (2024). DOI: 10.1038/s41586-024-08186-2

Amy Lanctot et al, Tomato engineering hits the sweet spot to make big sugar-rich fruit, Nature (2024). DOI: 10.1038/d41586-024-03302-8

Maternal stress linked to increased early onset epilepsy in children

 Researchers in Japan have linked maternal psychological distress during pregnancy to an increased risk of epilepsy in children.

Epilepsy affects 65 million people globally and is one of the most prevalent neurological disorders. Individuals with epilepsy often face discrimination and social stigma, enduring stress from living with a chronic, unpredictable disease.
Early onset of epilepsy before the age of three is associated with high rates of drug resistance and developmental delays. Previous studies have identified potential factors like placental abruption, eclampsia, infection during pregnancy, low birth weight, and artificial milk as risk factors for early childhood epilepsy.

In a research article, "The impact of maternal prenatal psychological distress on the development of epilepsy in offspring: The Japan Environment and Children's Study," published in PLOS ONE, researchers used a dataset obtained from the Japan Environment and Children's Study, a nationwide birth cohort involving nearly 100,000 participants, to evaluate the association between six-item Kessler Psychological Distress Scale (K6) scores of mothers and epilepsy among 1 to 3-year-olds.

Self-reported data on 97,484 children were retrospectively analyzed for connections between the stress scores of expecting mothers and epilepsy outcomes in their children.

Maternal psychological distress was assessed using the six-item Kessler Psychological Distress Scale (K6), administered twice during pregnancy: once in the first half (median 15.1 weeks) and again in the second half (median 27.4 weeks). Participants were categorized into six groups based on K6 scores, classified as either low (4 or less) or moderate (5 or 6) distress at each time point.
Children diagnosed with epilepsy at ages 1, 2, and 3 numbered 89 (0.1%), 129 (0.2%), and 149 (0.2%), respectively. Findings indicated that a maternal K6 score of 5 or higher at both time points was associated with 70% higher epilepsy diagnosis ratios among children aged 1 to 3 years. Multivariate analysis confirmed this association, even after adjusting for potential confounding factors like low birth weight and chromosomal abnormalities.

The study concludes that "...environmental adjustments to promote relaxation in pregnant women are needed," which makes a tremendous amount of good sense, though they continue "...to prevent the development of epilepsy in their offspring," which might be a little more than what the study is actually telling us.

Part 1

The 70% increase is significant, though even with high maternal stress, epilepsy remains an extremely rare condition, and other factors seemed more prominent in the study analyses. Low birth weight was associated with a 180% increased risk by age 1, introduction to artificial milk in the first month showed a 203% increased risk by age 2, and having any chromosome abnormalities increased the risk by 2100% at age 1, 1567% at age 2, and 1000% at age 3.

 Yuto Arai et al, The impact of maternal prenatal psychological distress on the development of epilepsy in offspring: The Japan Environment and Children's Study, PLOS ONE (2024). DOI: 10.1371/journal.pone.0311666

Part 2

Detecting cancer in urine: Nanowire-based capture of micro-ribonucleic acids

Cancer has a high death rate with delayed diagnosis of the disease being one of the main reasons for its fatality. Early diagnosis of cancer is vital to improving patient outcomes and in recent years, the development of diagnostic tools to detect early-stage cancer has gained a lot of attention.

Cancer cells utilize specific micro-ribonucleic acids (miRNAs)-small noncoding RNAs to regulate gene expression and promote tumor formation. While circulating miRNAs are viable biomarkers of early cancer disease, the identification of cancer-related miRNAs in blood and other body fluids remains a challenge.

In this light, a team of researchers have focused their efforts on nanowire-based miRNA extraction and machine learning (ML) analysis to detect cancer-associated miRNAs in urine. Their research findings were published online in the journal Analytical Chemistry on October 18, 2024.

Circulating miRNAs in the blood are mostly encapsulated in extracellular vesicles (EVs) and carry critical regulatory information. These miRNAs differ between healthy individuals and those with cancer. By utilizing zinc oxide (ZnO) nanowires to capture and extract miRNAs in urine, the research group has attempted to develop a non-invasive cancer detection tool.

Initially, the scientists utilized ZnO nanowires to capture EVs in urine samples and incorporated microarray technology to identify specific gene sequences in EV-encapsulated miRNAs. The ultracentrifugation technique was further used to compare and validate the efficiency of miRNA capture by nanowires.

The results revealed that EVs containing miRNAs, including exosomes-unique subtypes of EVs with sizes ranging from 40 nm to 200 nm, were efficiently captured on nanowires. Moreover, the presence of 2,486 miRNA species was confirmed during the miRNA profiling analysis of 200 urine samples.

Driven by the discovery of more than 2,000 miRNA species in urine samples, Yasui and the team hypothesized that most of the miRNAs in blood could be transferred to urine during the filtration process in kidneys. Subsequently, they employed a logistic regression classifier constructed using ML to identify lung cancer-associated urinary miRNA ensembles. The findings revealed one particular urinary miRNA ensemble, composed of 53 miRNA species, that could differentiate cancer and noncancer subjects with very high specificity and sensitivity.

Takao Yasui et al, Early Cancer Detection via Multi-microRNA Profiling of Urinary Exosomes Captured by Nanowires, Analytical Chemistry (2024). DOI: 10.1021/acs.analchem.4c02488

Scientists find a new way of entangling light and sound

For a wide variety of emerging quantum technologies, such as secure quantum communications and quantum computing, quantum entanglement is a prerequisite. Scientists at the Max-Planck-Institute for the Science of Light (MPL) have now demonstrated a particularly efficient way in which photons can be entangled with acoustic phonons.

The researchers were able to demonstrate that this entanglement is resilient to external noise, the usual pitfall of any quantum technology to date. They published their research in Physical Review Letters.

Changlong Zhu et al, Optoacoustic Entanglement in a Continuous Brillouin-Active Solid State System, Physical Review Letters (2024). DOI: 10.1103/PhysRevLett.133.203602

Quantum entanglement is a phenomenon in which particles become interconnected such that the state of one instantly influences the state of the other, regardless of the distance between them. Entanglement is an important phenomenon for many quantum technology applications because it can lead to secure quantum communications and high-dimensional quantum computing.

As photons, quanta of light, can propagate extremely fast while carrying quantum information, the entangling of pairs of photons via nonlinear optics is an established procedure.

Scientists at MPL have recently tackled the issue of establishing entanglement between very different entities, such as traveling sound waves, phonons, and optical photons. The proposed optoacoustic entanglement scheme is based on Brillouin scattering. It is particularly resilient, suitable for integration into quantum signal processing schemes and implementable at high environmental temperatures.
Entanglement has historically been fascinating at many different levels, as it strongly connects to our understanding of the fundamental laws of nature.

Quantum correlations among particles can persist even when separated by large distances. At the practical level, quantum entanglement is at the heart of many emerging quantum technologies. In the optical domain, entanglement of photons is fundamental to secure quantum communication methods or quantum computing schemes.
Photons, however, are volatile. Therefore, feasible alternatives are being sought for certain applications, such as quantum memory or quantum repeater schemes. One such alternative is the acoustic domain, where quanta are stored in acoustic or sound waves.

Scientists at the MPL have now indicated a particularly efficient way in which photons can be entangled with acoustic phonons: While the two quanta travel along the same photonic structures, the phonons move at a much slower speed. The underlying effect is the optical nonlinear effect known as Brillouin-Mandelstam scattering. It is responsible for coupling quanta at fundamentally different energy scales.

In their study, the scientists showed that the proposed entangling scheme can operate at temperatures in the tens of Kelvin. This is much higher than those required by standard approaches, which often employ expensive equipment such as dilution fridges. The possibility of implementing this concept in optical fibers or photonic integrated chips makes this mechanism of particular interest for use in modern quantum technologies.
Part 2

Spectacular chimneys discovered in the Dead Sea

Researchers have discovered meter-high chimneys on the floor of the Dead Sea. These are formed by the spontaneous crystallization of minerals from groundwater with an extremely high salt content flowing up out of the lake floor, they report in the journal Science of the Total Environment.

Discovered for the first time, these vents are an important early warning indicator for sinkholes. These subsidence craters form in the area surrounding the Dead Sea and pose a significant hazard to the population.

While black smokers along the mid-ocean ridge emit hot water containing sulfides at a depth of several thousand meters, the researchers in the Dead Sea discovered that highly saline groundwater flows out through the chimneys at the bottom of the lake.

Part 1

But where is the salt coming from? The explanation: The groundwater from the surrounding aquifers penetrates into the saline lake sediments, leaching out extremely old and thick layers of rock consisting mainly of the mineral halite. It then flows into the lake as brine.

Because the density of this brine is somewhat lower than that of the water in the Dead Sea, it rises upwards like a jet. It looks like smoke, but it's a saline fluid.
Contact with the lake water causes the dissolved salts, especially the halite, to spontaneously crystallize after emerging from the lake bed, where it forms the vents observed for the first time in the world. These can grow by several centimeters within a single day. Many of the slender chimneys were one to two meters high, but they also include giants more than seven meters high, with a diameter of more than 2–3 meters.
These white smokers are especially important because they can serve as an early warning indicator for sinkholes. These are subsidence craters up to 100 meters wide and up to 20 meters deep, thousands of which have formed along the Dead Sea in recent decades.

C. Siebert et al, A new type of submarine chimneys built of halite, Science of The Total Environment (2024). DOI: 10.1016/j.scitotenv.2024.176752

Part 2

Electric field signals reveal early warnings for extreme weather, study reveals

A new study  has made significant advances in understanding how atmospheric electric field measurements can help predict severe weather events.

The research paper, titled "Understanding heavy precipitation events in southern Israel through atmospheric electric field observations," is now published in Atmospheric Research.

By closely examining low-pressure winter weather systems, known as "Cyprus Lows," in the arid Negev Desert of southern Israel, this research reveals new insights into the role of the electric field in anticipating heavy precipitation.

Focusing on "wet" Cyprus Lows—situations where rain falls as a cold front moves through—researchers observed substantial increases in the potential gradient of the electric field. Minute-by-minute data showed potential gradient values rising sharply from typical fair-weather levels (about 100–200 volts per meter) to hundreds and even thousands of volts per meter during rainfall.

These surges occurred as convective clouds passed overhead, indicating that different cloud types produce unique electric field patterns. The study also highlighted that factors beyond rain intensity, such as cloud structure and the electrical charge of rain droplets, play roles in these electric fluctuations.

Through these findings, the researchers identified how electric field variations correlate with specific weather conditions. This enhanced understanding of electric field responses to weather events could significantly improve nowcasting systems for predicting extreme weather, particularly in regions prone to flash floods and sudden weather changes.

This research demonstrates how electric field variations can serve as indicators of shifting weather patterns, allowing us to anticipate severe weather events in real-time.

Roy Yaniv et al, Understanding heavy precipitation events in southern Israel through atmospheric electric field observations, Atmospheric Research (2024). DOI: 10.1016/j.atmosres.2024.107757

Living microbes discovered in Earth's driest desert 

The Atacama Desert, which runs along the Pacific Coast in Chile, is the driest place on the planet and, largely because of that aridity, hostile to most living things. Not everything, though—studies of the sandy soil have turned up diverse microbial communities. Studying the function of microorganisms in such habitats is challenging, however, because it's difficult to separate genetic material from the living part of the community from genetic material of the dead.

A new separation technique can help researchers focus on the living part of the community. This week in Applied and Environmental Microbiology, an international team of researchers describes a new way to separate extracellular (eDNA) from intracellular (iDNA) genetic material. The method provides better insights into microbial life in low-biomass environments, which was previously not possible with conventional DNA extraction methods.

The microbiologists used the novel approach on Atacama soil samples collected from the desert along a west-to-east swath from the ocean's edge to the foothills of the Andes mountains. Their analyses revealed a variety of living and possibly active microbes in the most arid areas.

Alexander Bartholomäus et al. Inside the Atacama Desert: uncovering the living microbiome of an extreme environment, Applied and Environmental Microbiology (2024). DOI: 10.1128/aem.01443-24 journals.asm.org/doi/10.1128/aem.01443-24

How does the brain keep calm? Insight into brain stability and the key role of NMDA receptors

Researchers  have made a fundamental discovery: the NMDA receptor (NMDAR)—long studied primarily for its role in learning and memory—also plays a crucial role in stabilizing brain activity.

By setting the "baseline" level for activity in neural networks, the NMDAR helps maintain stable brain function amidst continuous environmental and physiological changes. This discovery may lead to innovative treatments for diseases linked to disrupted neural stability, such as depression, Alzheimer's disease, and epilepsy.

In recent decades, brain research has mainly focused on processes that allow information encoding, memory, and learning, based on changes in synaptic connections between nerve cells. But the brain's fundamental stability, or homeostasis, is essential to support these processes.

This comprehensive project used three primary research methods: electrophysiological recordings from neurons in both cultured cells (in vitro) and living, behaving mice (in vivo) within the hippocampus, combined with computational modeling (in silico). Each approach provided unique insights into how NMDARs contribute to stability in neural networks.

These  findings suggest that ketamine's actions may stem from this newly discovered role of NMDAR: reducing the activity baseline in overactive brain regions seen in depression, like the lateral habenula, without interfering with homeostatic processes. This discovery could reshape our understanding of depression and pave the way for developing innovative treatments.

Antonella Ruggiero et al, NMDA receptors regulate the firing rate set point of hippocampal circuits without altering single-cell dynamics, Neuron (2024). DOI: 10.1016/j.neuron.2024.10.014