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Comment by Dr. Krishna Kumari Challa on September 11, 2024 at 6:57am

Longipteryx is part of a larger group of prehistoric birds called the enantiornithines, and this discovery marks the first time that scientists have found any stomach contents from an enantiornithine in China's Jehol Biota despite thousands of uncovered fossils.

"It's always been weird that we didn't know what they were eating, but this study also hints at a bigger picture problem in paleontology, that physical characteristics of a fossil don't always tell the whole story about what the animal ate or how it lived.
Since Longipteryx apparently wasn't hunting for fish, that leaves a question: what was it using its long, pointy beak and crazy-strong teeth for? The thick enamel is overpowered, it seems to be weaponized.
Weaponized beaks in hummingbirds have evolved at least seven times, allowing them to compete for limited resources. Clark suggested the hypothesis that perhaps Longipteryx's teeth and beak also served as a weapon, perhaps evolving under social or sexual selection.

Direct evidence of frugivory in the Mesozoic bird Longipteryx contradicts morphological proxies for diet, Current Biology (2024). DOI: 10.1016/j.cub.2024.08.012. www.cell.com/current-biology/f … 0960-9822(24)01124-2

Part 2

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Comment by Dr. Krishna Kumari Challa on September 11, 2024 at 6:55am

Paleontologists discover fossil birds with teeth had seeds in their stomachs, indicating that they ate fruit

For paleontologists who study animals that lived long ago, fossilized remains tell only part of the story of an animal's life. While a well-preserved skeleton can provide hints at what an ancient animal ate or how it moved, irrefutable proof of these behaviors is hard to come by. But sometimes, scientists luck out with extraordinary fossils that preserve something beyond the animal's body.

In a study published in the journal Current Biology, researchers found fossilized seeds in the stomachs of one of the earliest birds. This discovery shows that these birds were eating fruits, despite a long-standing hypothesis that this species of bird feasted on fish (and more recent hypotheses it ate insects) with its incredibly strong teeth.

Longipteryx chaoyangensis lived 120 million years ago in what's now northeastern China. It's among the earliest known birds, and one of the strangest.

This bird is weird. It had a  long skull, and teeth only at the tip of its beak. 

Tooth enamel is the hardest substance in the body, and Longipteryx's tooth enamel is 50 microns thick. That's the same thickness of the enamel on enormous predatory dinosaurs like Allosaurus that weighed 4,000 pounds, but Longipteryx is the size of a bluejay. 

Longipteryx was discovered in 2000, and at the time, scientists suggested that its kingfisher-like elongated skull meant that it too hunted fish. However, this hypothesis has been challenged by a number of scientists.

There are other fossil birds, like Yanornis, that ate fish, and scientists know because specimens have been found with preserved stomach contents, and fish tend to preserve well. Plus, these fish-eating birds had lots of teeth, all the way along their beaks, unlike how Longipteryx only has teeth at the very tip of its beak.

However, no specimens of Longipteryx had been found with fossilized food still in their stomachs for scientists to confirm what it ate— until now.

Since Longipteryx lived in a temperate climate, it probably wasn't eating fruits year-round;  scientists suspect that it had a mixed diet which included things like insects when fruits weren't available.

Part 1

Comment by Dr. Krishna Kumari Challa on September 11, 2024 at 6:37am

New Zealand's kākāpō developed different feather colors to evade predatory birds, genome sequencing shows

Evolution: Aotearoa New Zealand's flightless parrot, the kākāpō, evolved two different color types to potentially help them avoid detection by a now-extinct apex predator , researchers report in the open-access journal PLOS Biology.

The kākāpō (Strigops habroptilus) is a nocturnal, flightless parrot endemic to New Zealand. It experienced severe population declines after European settlers introduced new predators. By 1995 there were just 51 individuals left, but intense conservation efforts have helped the species rebound to around 250 birds. Kākāpō come in one of two colors—green or olive—which occur in roughly equal proportions.

To understand how this color variation evolved and why it was maintained despite population declines, researchers analyzed genome sequence data for 168 individuals, representing nearly all living kākāpō at the time of sequencing. They identified two genetic variants that together explain color variation across all the kākāpō they studied.

Scanning electron microscopy showed that green and olive feathers reflect slightly different wavelengths of light because of differences in their microscopic structure. The researchers estimate that olive coloration first appeared around 1.93 million years ago, coinciding with the evolution of two predatory birds: Haast's eagle and Eyles' harrier.

Computer simulations suggest that whichever color was rarer would have been less likely to be detected by predators, explaining why both colors persisted in the kākāpō population over time.

The results suggest that kākāpō coloration evolved due to pressure from apex predators that hunted by sight. This variation has remained even after the predators went extinct, around 600 years ago.

The authors argue that understanding the origins of kākāpō coloration might have relevance to the conservation of this critically endangered species. They show that without intervention, kākāpō color variation could be lost within just 30 generations, but it would be unlikely to negatively impact the species today.

Urban L, Santure AW, Uddstrom L, Digby A, Vercoe D, Eason D, et al. (2024) The genetic basis of the kākāpō structural color polymorphism suggests balancing selection by an extinct apex predator. PLoS Biology (2024). DOI: 10.1371/journal.pbio.3002755

Comment by Dr. Krishna Kumari Challa on September 10, 2024 at 11:47am

The Calls of Amazon Parrots are changing!

Some parrots in the Amazon no longer sound like they used to when they call out to each other through the trees.

Scientists studying the yellow-naped amazon (Amazona auropalliata) have noticed in the last few decades that these Pacific coast parrots are changing their 'accents'. While it could interfere with mating and reproduction, the researchers speculate it might actually be a positive sign of the birds adapting.

Like many other birds, yellow-naped parrots are known to have regional dialects. This means that different communities shriek, whistle, and screech in slightly different ways, depending on where they live.

Scientists have noticed this about the species since 1994, but between 2005 and 2016, researchers from New Mexico State University and the University of Pittsburgh (UPJ) at Johnstown have noticed a significant geographic shift.

The types of calls these parrots are making in different regions seem to be bleeding into one another.

Some calls that were recently heard in the north region, for instance, had only previously been heard in the south. In fact, some birds in the north were capable of producing both accents, researchers found, what they call a 'bilingual' skill.

This could possibly give the parrots a survival advantage. Birds that can communicate with more groups may be able to share more information, access foraging areas, or gain roosting privileges.

And that may be more important now than ever.

https://royalsocietypublishing.org/doi/10.1098/rspb.2024.0659

Comment by Dr. Krishna Kumari Challa on September 10, 2024 at 11:21am

Plastic pollution hotspots pinpointed in new research—India ranks top due to high levels of uncollected waste

Researchers have used machine learning to identify the biggest plastic pollution hotspots across more than 50,000 towns, cities and rural areas worldwide. Their new global model reveals the most detailed picture of plastic pollution ever created with the highest environmental concentrations in India, predominantly because so much of its waste isn't collected.

Open burning of waste is prolific, accounting for 57% of all plastic pollution worldwide by weight. This involves burning waste on open fires without any controls to prevent hazardous emissions from reaching the environment or harming our health. This practice is popular, possibly because it seems to make the waste disappear, reducing the burden on waste management authorities and reducing the unsightliness of waste dumped on land.
India has emerged as the largest plastic polluter, emitting 9.3 million tons of plastic into the environment each year—one fifth of the total. That's 2.7 times more than the next two largest polluters, Nigeria and Indonesia.

India comes top because only 81% of its waste is collected. But, it also generates a lot more waste than some previous models have assumed. Official government sources estimate 0.12kg per person per day, but these estimates exclude many rural areas, so the real number is closer to 0.54kg per person per day. The combination of such a large amount of waste, large population and low collection rate creates the conditions under which plastic pollution flourishes.

https://www.nature.com/articles/s41586-024-07758-6

Comment by Dr. Krishna Kumari Challa on September 10, 2024 at 11:18am

Iron was life's 'primeval' metal, say scientists

Every living organism uses tiny quantities of metals to carry out biological functions, including breathing, transcribing DNA, turning food into energy, or any number of essential life processes.

Life has used metals in this way since single-celled organisms floated in Earth's earliest oceans. Nearly half of the enzymes—proteins that carry out chemical reactions in cells—within organisms require metals, many of which are transition metals named for the space they occupy in the periodic table.

Now, a team of scientists argue that iron was life's earliest, and sole, transition metal. Their study, titled "Iron: Life's primeval transition metal," is published in the Proceedings of the National Academy of Sciences.

They argue that life only relied on metals that it could interact with, and the iron-rich early ocean would make other transition metals essentially invisible.

Early oceans were rich in iron—specifically, an ion of iron called Fe(II). Fe(II) can be readily dissolved in water and would have been the primary metal found in oceans during the Archean Eon, a geologic time period that began about 4 billion years ago and ended about 2.5 billion years ago.

The end of the Archean Eon was marked by something called the Great Oxygenation Event. At this time, life evolved the ability to perform oxygen-producing photosynthesis. Over the next billion years, Earth's ocean transformed from an iron-rich, anoxic sea to today's oxygenated body of water, according to the researchers. This also oxidized Fe(II) into Fe(III), rendering it insoluble.

Geologists knew of iron's ubiquity on Earth during this time, it wasn't until they began talking with Valentine that they realized how great an impact iron might have had on early life.

Life, in the face of orders of magnitude more iron than other metals, couldn't know to evolve toward such a sophisticated way of managing them. The fall of the abundance of iron forced life to manage these other metals to survive, but that also enabled new functions and the diversity of life we have today.

Johnson, Jena E., Iron: Life's primeval transition metal, Proceedings of the National Academy of Sciences (2024). DOI: 10.1073/pnas.2318692121. doi.org/10.1073/pnas.2318692121

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Comment by Dr. Krishna Kumari Challa on September 10, 2024 at 11:09am

There are several reasons why most cities receive more rainfall than their rural neighbors.
One key factor is the presence of tall buildings, which block or slow down wind speeds. This leads to a convergence of air toward the city center.
The buildings further enhance this convergence by slowing the winds, resulting in a stronger upward motion of air. This upward motion promotes the condensation of water vapor and cloud formation, which are critical conditions for producing rainfall and precipitation.
Researchers found that population has the largest correlation with urban precipitation anomalies compared to other environmental and urbanization factors. This is because larger populations typically create denser and taller urban areas, along with more greenhouse gas emissions, and therefore more pronounced heat.
This phenomenon has implications for all cities heading into a future of climate change.
the increased chances of rainfall in cities combined with the impervious surfaces that make up their urban environments can be a recipe for flash flooding.

Niyogi, Dev, Global scale assessment of urban precipitation anomalies, Proceedings of the National Academy of Sciences (2024). DOI: 10.1073/pnas.2311496121. doi.org/10.1073/pnas.2311496121

Part2

Comment by Dr. Krishna Kumari Challa on September 10, 2024 at 11:07am

Global study shows that most cities receive more rainfall than surrounding rural areas

The effect of urbanization on temperature is relatively well-known: cities are often measurably warmer than their surrounding rural areas. This is called the urban heat island effect. What fewer people know is that the urban heat island has a twin counterpart with similarly important consequences: the urban precipitation anomaly, where the presence of urban development measurably affects the amount of rainfall in an area.

In a study published in Proceedings of the National Academy of Sciences, researchers looked for evidence of precipitation anomalies in 1,056 cities across the globe and found that more than 60% of those cities receive more precipitation than their surrounding rural areas.

In some cases, the difference can be significant. For instance, researchers found that Houston, on average, will receive almost 5 inches more rain per year than its surrounding rural areas.

This could have wide-ranging implications, the most serious of which is worsened flash flooding in densely built urban areas.

Variation in urban rainfall is something scientists have known about for several decades, but never at a global scale. Previous studies only looked at certain cities and storm cases.

Urban areas tend to take rain from one location and concentrate it in another, much like a sponge that is being squeezed. If you were to pinch one part of the sponge, you would have water coming down more forcefully from one side. The amount of water you have in the sponge is the same, but because now you have that dynamic sort of squeezing the atmosphere, you have more ability to take the water out from that location.

Although it's less common, some urban areas actually receive less rainfall than their surrounding rural counterparts. This typically occurs in cities situated in valleys and lowlands, where precipitation patterns are controlled by nearby mountains. The cities where this is most pronounced include Seattle, Washington; Kyoto, Japan; and Jakarta, Indonesia.

Part1

Comment by Dr. Krishna Kumari Challa on September 10, 2024 at 10:56am

To understand that critical part of the process, the research team turned to colloidal crystals—particles that are about 10,000 times larger than atoms and spontaneously form a crystal structure at high concentrations. These crystals are used to mimic atomic systems because they have the same structures, undergo the same phase transitions, and possess the same types of defects. Colloidal crystals, however, are very soft—even 100,000 times softer than Jell-O.

The researchers grew these colloidal crystals composed of millions of particles and observed each particle using a confocal optical microscope. When they applied a strain to these crystals, they could measure the motion of each and every particle.

Surprisingly, these colloidal crystals experience significant work hardening—even more strongly than any other material. In fact, when the difference in particle size is taken into account, these ultra-soft materials become much stronger than most metals.
It is the first time that work hardening has been observed in colloidal crystals; it reveals that the process is governed primarily by the geometry of the particles and the defects. The crystals became stronger because of the dislocation defects, how they interact and entangle with one another.

These observations reveal the universal mechanisms of work hardening which will also apply more generally to all materials.

Seongsoo Kim et al, Work hardening in colloidal crystals, Nature (2024). DOI: 10.1038/s41586-024-07453-6

Part 2

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Comment by Dr. Krishna Kumari Challa on September 10, 2024 at 10:54am

Why do materials get stronger when they are deformed? Research sheds light on universal mechanisms of work hardening

The earliest blacksmiths in the Bronze and Iron Ages figured out that when they deformed metal through bending or hammering, it became stronger. This process, known as work or strain hardening, is still used widely in metallurgy and manufacturing today to increase the strength of everything from car frames to overhead power wires. But materials scientists have never been able to watch this essential process unfold in real time—until now.

A team of scientists  have observed, for the first time, the detailed mechanisms driving the fundamental process of work hardening.

It's been impossible to observe work hardening in metals in real time because the atomic structures can only be observed through an electron microscope. Researchers can compare the structure before and after deformation but have had only a limited view into what happens during the process. Previous research has revealed that imperfections in the structure, known as dislocations, form a network of defects which cause the work hardening.

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