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Comment by Dr. Krishna Kumari Challa on September 18, 2025 at 10:02am

Research has also recently revealed that lithornithids may have had a bony organ on the tip of their beaks which made them excel at foraging for insects.

But what about the second condition—a lack of predators?

Researchers suspect that paleognath ancestors likely started evolving towards flightlessness after dinosaurs went extinct around 65 million years ago.

With all the major predators gone, ground-feeding birds would have been free to become flightless, which would have saved them a lot of energy.

The small mammals that survived the event that wiped out the dinosaurs would have taken some time to evolve into predators.

This would have given flightless birds "time to adapt by becoming swift runners" like the emu, ostrich and rhea—or even "becoming themselves dangerous and intimidating, like the cassowary.

Quantitative analysis of stem-palaeognath flight capabilities sheds light on ratite dispersal and flight loss, Biology Letters (2025). DOI: 10.1098/rsbl.2025.0320. royalsocietypublishing.org/doi … .1098/rsbl.2025.0320

Part 2

Comment by Dr. Krishna Kumari Challa on September 18, 2025 at 9:59am

Ostrich and emu ancestor could fly, scientists discover

How did the ostrich cross the ocean?

We have long been puzzled by how the family of birds that includes African ostriches, Australian emus and cassowaries, New Zealand kiwis and South American rheas spread across the world—given that none of them can fly.

However, a study published this week may have found the answer to this mystery: the family's oldest-known ancestors were able to take wing.

The only currently living member of this bird family—which is called paleognaths—capable of flight is the tinamous in Central and South America. But even then, the shy birds can only fly over short distances when they need to escape danger or clear obstacles.

Researchers analyzed the specimen of a lithornithid, the oldest paleognath group for which fossils have been discovered. They lived during the Paleogene period 66–23 million years ago.

The fossil of the bird Lithornis promiscuus was first found in the US state of Wyoming, but had been sitting in the Smithsonian museum's collection.

Because bird bones tend to be delicate, they are often crushed during the process of fossilization, but this one was not. 

Crucially for this study, it retained its original shape. This allowed the researchers to scan the animal's breastbone, which is where the muscles that enable flight would have been attached.

They determined that Lithornis promiscuus was able to fly—either by continuously beating its wings or alternating between flapping and gliding.

But  why did these birds give up the power of flight?

Birds tend to evolve flightlessness when two important conditions are met: they have to be able to obtain all their food on the ground, and there cannot be any predators to threaten them.

Part 1

Comment by Dr. Krishna Kumari Challa on September 18, 2025 at 9:50am

Coral reefs set to stop growing as climate warms

Most coral reefs will soon stop growing and may begin to erode—and almost all will do so if global warming hits 2°C, according to a new study in the western Atlantic. 

The study, published in the journal Nature, projects that more than 70% of the region's reefs will stop growing by 2040—and over 99% will do so by 2100 if warming reaches 2°C or more above pre-industrial levels. The paper is titled "Reduced Atlantic reef growth past 2°C warming amplifies sea-level impacts."

Climate change—along with other issues such as coral disease and deteriorating water quality—reduces overall reef growth by killing corals and impacting colony growth rates, the study concludes.

 Chris Perry, Reduced Atlantic reef growth past 2°C warming amplifies sea-level impacts, Nature (2025). DOI: 10.1038/s41586-025-09439-4. www.nature.com/articles/s41586-025-09439-4

Comment by Dr. Krishna Kumari Challa on September 18, 2025 at 9:37am

Some small asteroids can abruptly explode

Some asteroids are more dangerous than others, according to a report published in Nature Astronomy by an international team of researchers.

The team had presented their findings of an investigation into the impact of small asteroid 2023 CX1 over France in February 2023. This new paper revealed that small asteroids can explode on atmospheric entry.

The researchers confirmed the existence of a new population of asteroids linked to L-type chondrites, capable of fragmenting abruptly in the atmosphere and releasing almost all their energy at once. 

Such asteroids must be accounted for in planetary defense strategies, as they pose an increased risk to populated areas, they say.

Auriane Egal et al, Catastrophic disruption of asteroid 2023 CX1 and implications for planetary defence, Nature Astronomy (2025). DOI: 10.1038/s41550-025-02659-8.

Comment by Dr. Krishna Kumari Challa on September 18, 2025 at 9:25am

Estimated 16,500 climate change deaths during Europe summer: Study

Scientists estimated this week that rising temperatures from human-caused climate change were responsible for roughly 16,500 deaths in European cities this summer, using modeling to project the toll before official data is released.

The rapidly produced study is the latest effort by climate and health researchers to quickly link the death toll during heat waves to global warming—without waiting months or years to be published in a peer-reviewed journal.

The estimated deaths were not actually recorded in the European cities, but instead were a projection based on methods such as modeling used in previously peer-reviewed studies.

Death tolls during heat waves are thought to be vastly underestimated because the causes of death recorded in hospitals are normally heart, breathing or other health problems that particularly affect the elderly when the mercury soars.

researchers used climate modeling to estimate that global warming made temperatures an average of 2.2 degrees Celsius hotter in 854 European cities between June and August.

Using historical data indicating how such soaring temperatures drive up mortality rates, the team estimated there were around 24,400 excess deaths in those cities during that time.

They then compared this number to how many people would have died in a world that was not 1.3C warmer due to climate change caused by humans burning fossil fuels.

Nearly 70%—16,500—of the estimated excess deaths were due to global warming, according to the rapid attribution study.

This means climate change could have tripled the number of heat deaths this summer, said the study from scientists at Imperial College London and epidemiologists at the London School of Hygiene & Tropical Medicine.

The estimates did reflect previous peer-reviewed research, such as a Nature Medicine study which determined there were more than 47,000 heat-related deaths during the European summer of 2023.

Numerous prominent climate and health researchers also backed the study.

What makes this finding even more alarming is that the methods used in these attribution studies are scientifically robust, yet conservative.

The actual death toll could be even higher, warn the researchers. And what about if the figures for the entire world taken into account! Extremely alarming.

Source: Nature Medicine

Comment by Dr. Krishna Kumari Challa on September 18, 2025 at 9:13am

Study provides first evidence that plastic nanoparticles can accumulate in the edible parts of vegetables

Plastic pollution represents a global environmental challenge, and once in the environment, plastic can fragment into smaller and smaller pieces.

A new study shows for the first time that some of the tiniest particles found in the environment can be absorbed into the edible sections of crops during the growing process.

The research used radishes to demonstrate, for the first time, that nanoplastics—some measuring as little as one millionth of a centimeter in diameter—can enter the roots, before spreading and accumulating into the edible parts of the plant.

The researchers say the findings reveal another potential pathway for humans and animals to unintentionally consume nanoplastics and other particles and fibers that are increasingly present in the environment.

It also underscores the need for further research to investigate what is an emerging food safety issue, and the precise impacts it could have on environmental and human health.

This study provides clear evidence that particles in the environment can accumulate not only in seafood but also in vegetables. This work forms part of our growing understanding on accumulation, and the potentially harmful effects of micro- and nanoparticles on human health.

Nathaniel J. Clark et al, Determining the accumulation potential of nanoplastics in crops: An investigation of 14C-labelled polystyrene nanoplastic into radishes, Environmental Research (2025). DOI: 10.1016/j.envres.2025.122687

Comment by Dr. Krishna Kumari Challa on September 18, 2025 at 9:04am

A new explanation for Siberia's giant exploding craters

Scientists may be a step closer to solving the mystery of Siberia's giant exploding craters. First spotted in the Yamal and Gydan peninsulas of Western Siberia in 2012, these massive holes, known as giant gas emission craters (GECs) can be up to 164 feet deep. They seem to appear randomly in the permafrost and are formed when powerful explosions blast soil and ice hundreds of feet into the air.

For more than a decade, researchers have been coming up with theories about the origin of these craters, ranging from meteor impacts to gas explosions. However, none of these have been able to explain why the craters are only found in this specific area and not in the permafrost elsewhere in the Arctic.

Now, research published in the journal Science of the Total Environment proposes a new and more complete explanation that links the craters to specific factors unique to the two peninsulas, the vast gas reserves in this region and the effects of climate change.

"We propose that the formation of GECs is linked to the specific conditions in the area, including abundant natural gas generation and seepage and the overall limited thickness of the continuous permafrost," wrote the researchers in their paper.

According to their model, GECs form when gas and heat rise from deep underground. The heat melts the permafrost seal (a layer of permanently frozen ground that acts as a lid), making it thinner. Meanwhile, the gas builds up underneath it, and with nowhere to go, the pressure rises. As the climate warms, the permafrost thaws even more, making the lid thinner. Eventually, pressure becomes too great and causes an explosive collapse that creates a large crater.

 Helge Hellevang et al, Formation of giant Siberian gas emission craters (GECs), Science of The Total Environment (2025). DOI: 10.1016/j.scitotenv.2025.180042

Exploding Siberian Craters

Comment by Dr. Krishna Kumari Challa on September 17, 2025 at 10:18am

Man's COVID Infection Lasted 2 Years, Setting a New Record

An immunocompromised man endured ongoing acute COVID-19 for more than 750 days. During this time, he experienced persistent respiratory symptoms and was hospitalized five times.
In spite of its duration, the man's condition differs from long COVID as it wasn't a case of symptoms lingering once the virus had cleared out, but the viral phase of SARS-CoV-2 that continued for over two years.

While this record may be easy to dismiss as something that occurs only to vulnerable people, persistent infections have implications for us all, researchers warn in their new study.

https://www.thelancet.com/journals/lanmic/article/PIIS2666-5247(25)00050-3/fulltext

Comment by Dr. Krishna Kumari Challa on September 17, 2025 at 10:10am

Researchers used two different and powerful methods—single cell RNA sequencing and advanced 3D imaging. They studied samples from both healthy and transplant rejection patients.

Single-cell sequencing allows scientists to study the activity of genes in individual cells, one at a time. The researchers did this on a very large scale to generate a huge amount of data. Then the team stained large chunks of kidney tissue while still intact and used a procedure to make it transparent. This 3D imaging helped validate the predictions from the single-cell genetic analysis.

The researchers found that during kidney transplant rejection, the lymphatic vessels within the transplant change their shape and organization. The vessels spread into deeper parts of the kidney known as the medulla, which normally has no lymphatic vessels within it. At the same time, the cell junctions, which are protein anchors that connect cells, go from looking like loose buttons to tightening up like zippers. This is a change that in other contexts is associated with immune cells getting trapped and unable to escape.

Additionally, the researchers found that the balance of T cells inside and around the vessels was disrupted. These T cells released signals that made the vessels switch on molecules acting like "brakes" for the immune system, in an attempt to calm inflammation. However, this protective response was not enough, as other immune cells and antibodies were seen to be directly attacking the kidney. Strikingly, the vessels themselves were also carrying signs that they too were being targeted by the same harmful antibodies.
These findings challenge the view that lymphatic vessels are simply good or bad in transplant rejection. This study suggests that the lymphatic system is normally protective but impaired in transplant rejection as the findings show the vessels change in ways that could encourage rejection by altering their structure and fueling immune responses. The results pave the way for research to focus on regenerating or protecting the lymphatic system in chronic kidney rejection.

Daniyal J. Jafree et al, Organ-specific features of human kidney lymphatics are disrupted in chronic transplant rejection, Journal of Clinical Investigation (2025). DOI: 10.1172/jci168962

Part 2

Comment by Dr. Krishna Kumari Challa on September 17, 2025 at 10:08am

Kidney transplant rejection associated with changes in lymphatic vessels, new research shows

Scientists have uncovered how lymphatic vessels—the kidney's "plumbing system"—undergo dramatic changes during chronic transplant rejection, becoming structurally disorganized and spreading to unusual parts of the kidney.

Researchers used single-cell sequencing combined with powerful 3D imaging to look at small lymphatic vessels in kidney tissue, comparing healthy kidneys with transplanted kidneys that had been rejected.

Published in the Journal of Clinical Investigation, the research sheds new light on a major unsolved challenge in kidney transplantation and could open the door to new treatments that help transplants last longer.
Kidney transplantation is the most common form of solid organ transplant worldwide. Although the short-term outcomes of kidney transplantation—within a year after surgery—are very good, the long-term outcomes are poorer. Within 10 years, and depending on what country patients are treated in, roughly 50% of kidney grafts will fail.

Researchers know that a big component of why kidney transplant failure occurs is that the patient's immune system attacks parts of the new kidney—such as the blood vessels within it. However, the role of the lymphatic vessels is far less understood. In healthy kidneys, lymphatic vessels act as the organ's plumbing system—playing a vital role in draining excess fluid and helping to regulate immune activity. Therefore, the researchers sought to gain a deeper understanding of the lymphatic system during transplant rejection.

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