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Comment by Dr. Krishna Kumari Challa on December 21, 2024 at 10:25am

Hidden hazards of chemical mixtures in rivers

Artificial intelligence can provide critical insights into how complex mixtures of chemicals in rivers affect aquatic life—paving the way for better environmental protection.

A new approach, developed by researchers  demonstrates how advanced artificial intelligence (AI) methods can help identify potentially harmful chemical substances in rivers by monitoring their effects on tiny water fleas (Daphnia).

International researchers from various countries  analyzed water samples from the Chaobai River system near Beijing. This river system is receiving chemical pollutants from a number of different sources, including agricultural, domestic and industrial.

There is a vast array of chemicals in the environment. Water safety cannot be assessed one substance at a time. Now we have the means to monitor the totality of chemicals in sampled water from the environment to uncover what unknown substances act together to produce toxicity to animals, including humans, say the researchers.

The results, published in Environmental Science and Technology, reveal that certain mixtures of chemicals can work together to affect important biological processes in aquatic organisms, which are measured by their genes. The combinations of these chemicals create environmental hazards that are potentially greater than when chemicals are present individually.

The research team used water fleas (Daphnia) as test organisms in the study because these tiny crustaceans are highly sensitive to water quality changes and share many genes with other species, making them excellent indicators of potential environmental hazards.

Part 1

Comment by Dr. Krishna Kumari Challa on December 21, 2024 at 10:15am

We now have so much data that in the 21st century we can finally answer the question—how and why does a simple average expansion law emerge from complexity?

"A simple expansion law consistent with Einstein's general relativity does not have to obey Friedmann's equation."

The researchers say that the European Space Agency's Euclid satellite, which was launched in July 2023, has the power to test and distinguish the Friedmann equation from the timescape alternative. However, this will require at least 1,000 independent high quality supernovae observations.

When the proposed timescape model was last tested in 2017, the analysis suggested it was only a slightly better fit than the ΛCDM as an explanation for cosmic expansion, so the present  team worked closely with the Pantheon+ collaboration team who had painstakingly produced a catalog of 1,535 distinct supernovae.

They say the new data now provides "very strong evidence" for timescape. It may also point to a compelling resolution of the Hubble tension and other anomalies related to the expansion of the universe.

Further observations from Euclid and the Nancy Grace Roman Space Telescope are needed to bolster support for the timescape model, the researchers say.

 Antonia Seifert et al, Supernovae evidence for foundational change to cosmological models, Monthly Notices of the Royal Astronomical Society: Letters (2024). DOI: 10.1093/mnrasl/slae112

Part 3

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Comment by Dr. Krishna Kumari Challa on December 21, 2024 at 10:13am

Dark energy is commonly thought to be a weak anti-gravity force which acts independently of matter and makes up around two thirds of the mass-energy density of the universe.

The standard Lambda Cold Dark Matter (ΛCDM) model of the universe requires dark energy to explain the observed acceleration in the rate at which the cosmos is expanding.

Scientists base this conclusion on measurements of the distances to supernova explosions in distant galaxies, which appear to be farther away than they should be if the universe's expansion were not accelerating.

However, the present expansion rate of the universe is increasingly being challenged by new observations.

Firstly, evidence from the afterglow of the Big Bang—known as the Cosmic Microwave Background (CMB)—shows the expansion of the early universe is at odds with current expansion, an anomaly known as the "Hubble tension."

In addition, recent analysis of new high precision data by the Dark Energy Spectroscopic Instrument (DESI) has found that the ΛCDM model does not fit as well as models in which dark energy is "evolving" over time, rather than remaining constant.

Both the Hubble tension and the surprises revealed by DESI are difficult to resolve in models which use a simplified 100-year-old cosmic expansion law—Friedmann's equation.

This assumes that, on average, the universe expands uniformly—as if all cosmic structures could be put through a blender to make a featureless soup, with no complicating structure. However, the present universe actually contains a complex cosmic web of galaxy clusters in sheets and filaments that surround and thread vast empty voids.

Part 2

Comment by Dr. Krishna Kumari Challa on December 21, 2024 at 10:07am

Dark energy 'doesn't exist' so can't be pushing 'lumpy' universe apart, physicists say

One of the biggest mysteries in science—dark energy—doesn't actually exist, according to researchers looking to solve the riddle of how the universe is expanding.

Their analysis has been published in the journal Monthly Notices of the Royal Astronomical Society Letters.

For the past 100 years, physicists have generally assumed that the cosmos is growing equally in all directions. They employed the concept of dark energy as a placeholder to explain unknown physics they couldn't understand, but the contentious theory has always had its problems.

Now a team of physicists and astronomers are challenging the status quo, using improved analysis of supernovae light curves to show that the universe is expanding in a more varied, "lumpier" way.

The new evidence supports the "timescape" model of cosmic expansion, which doesn't have a need for dark energy because the differences in stretching light aren't the result of an accelerating universe but instead a consequence of how we calibrate time and distance.

It takes into account that gravity slows time, so an ideal clock in empty space ticks faster than inside a galaxy.

The model suggests that a clock in the Milky Way would be about 35 percent slower than the same one at an average position in large cosmic voids, meaning billions more years would have passed in voids. This would in turn allow more expansion of space, making it seem like the expansion is getting faster when such vast empty voids grow to dominate the universe.

These findings show that we do not need dark energy to explain why the universe appears to expand at an accelerating rate. Dark energy is a misidentification of variations in the kinetic energy of expansion, which is not uniform in a universe as lumpy as the one we actually live in.

The research provides compelling evidence that may resolve some of the key questions around the quirks of our expanding cosmos.

With new data, the universe's biggest mystery could be settled by the end of the decade, the physicists say.

Part 1

Comment by Dr. Krishna Kumari Challa on December 20, 2024 at 1:03pm

Squirrels Have Developed a Taste For Meat in Surprise Discovery
Squirrels might look like adorable, nut-hoarding furballs, but some are ruthless predators that hunt, tear apart, and devour voles.

That's the startling finding of a new study published this week in the Journal of Ethology – the first to document widespread carnivorous behavior in these seemingly innocent creatures.
The observations were made this summer, during the 12th year of a long-term study conducted at Briones Regional Park in Contra Costa County, California.

Between June and July, researchers recorded 74 interactions involving California ground squirrels and voles, with 42 percent of them involving active hunting of their fellow rodents.
It was previously known that as many as 30 species of squirrels opportunistically consume meat, ranging from small fish to birds. However, it was unclear whether this behavior stemmed from scavenging or active predation.

The new study is the first to confirm that hunting is, in fact, a common behavior.

Researchers observed squirrels crouching low to the ground before ambushing their prey, though more often, they chased voles, pounced, and delivered a neck bite followed by vigorous shaking.

The study also found that the squirrels' carnivorous behavior peaked during the first two weeks of July, coinciding with a surge in vole populations.

https://link.springer.com/article/10.1007/s10164-024-00832-6

Comment by Dr. Krishna Kumari Challa on December 20, 2024 at 10:35am

New discovery pinpoints when good cholesterol becomes harmful

We have heard till now that good cholesterol is good. But wait ....

Researchers have discovered that certain components of so-called "good" cholesterol—high-density lipoproteins (HDL)—may be associated with an increased prevalence of cardiovascular disease.

Surprized? Yes, new data asks for revisits.

Yes, not all cholesterol is born the same. What is not commonly recognized is that each type of cholesterol has two forms—free cholesterol, which is active and involved in cellular functions, and esterified, or bound, cholesterol, which is more stable and ready to be stored in the body. Too much free cholesterol, even if it is in HDL, could contribute to heart disease. Hmmm!

In pre-clinical studies, the research team discovered that HDL with a high content of free cholesterol is likely dysfunctional. To validate their findings and prove their hypothesis, they are currently at the halfway point of the Houston Heart Study in which they will be studying 400 patients with a range of plasma HDL concentrations.

The most surprising finding from  this new study thus far is that there is a strong link between the amount of free cholesterol in HDL and how much of it accumulates in white blood cells called macrophages, which can contribute to heart disease.

While it was previously thought that the transfer of free cholesterol to HDL was beneficial for heart health by removing excess cholesterol from tissues, the new data shows that in the context of high plasma HDL concentrations, the reverse is true, wherein free cholesterol transfer from HDL to the white blood cells in blood and tissues could actually raise one's risk for cardiovascular disease.

The researchers say once they reach their immediate goal of showing that excess free cholesterol in HDL is associated with excess cardiovascular disease, they plan to develop new diagnostics and treatments for managing heart disease, as well as use HDL-free cholesterol as a biomarker to identify patients requiring HDL-lowering therapies.

Now that you are confused, what should you do?

Wait for more clarification and confirmation studies while still taking care of your heart's health.

Dedipya Yelamanchili et al, HDL-free cholesterol influx into macrophages and transfer to LDL correlate with HDL-free cholesterol content, Journal of Lipid Research (2024). DOI: 10.1016/j.jlr.2024.100707

Comment by Dr. Krishna Kumari Challa on December 20, 2024 at 10:26am

Adding sweetener to coffee enhances 'night-owl' effects of caffeine, research reveals

Adding sugar or artificial sweeteners to coffee disrupted the body clocks in mice more than coffee on its own, researchers have found, with it causing day and night to be reversed in some mice. If this holds for humans as well, adding sweetener to coffee would have significant health ramifications.

If you need to perk yourself up in the morning, or stay up late to get some work or a school assignment done, most people will make themselves a cup of coffee or grab an energy drink containing caffeine. These "night-owl" effects of that perky chemical are far from unknown.

A myriad of epidemiological studies have demonstrated how night-oriented people tend to drink more caffeinated beverages than morning people, and experiments on animals and cells have shown how caffeine works to extend the waking period of the internal body clock.

But a group of researchers accidentally discovered that changes in the activity rhythms of mice were affected even more strongly when they mixed caffeine with sugar or other sweeteners.

The mice that had consumed the caffeine-sweetener mix experienced a very long "free-running" sleep-wake period of 26–30 hours, and some even switched from a nocturnal circadian rhythm to a daytime-based one.

These effects continued to happen even when the mice were subjected to persistent darkness. This latter phenomenon suggests that the caffeine-sweetener effect is operating independently of the central regulator of the internal body clock, the suprachiasmatic nucleus (SCN), which lies in the hypothalamus in the brain. That central regulator itself is normally governed by light and the natural day-night cycle, and it in turn ensures a synchronization of clocks situated in organ tissue elsewhere in the body.

The researchers think that the combination of caffeine and sweetness may be creating a conflicting signal within the body possibly mediated by another famous chemical, dopamine. Both caffeine and sweeteners activate the reward system in the brain, leading to the release of dopamine. It is this double hit of dopamine that could be contributing to the emergence of the long-period activity rhythms.

The researchers now aim to investigate further the possible dopamine link and see whether the boost to caffeine produced by a sweetener is replicated in humans. While this initial study only looked at the effects in mice, the findings may have important implications for our understanding of how sweetened caffeine affects human health.

 Yu Tahara et al, Sweetened caffeine drinking revealed behavioral rhythm independent of the central circadian clock in male mice, npj Science of Food (2024). DOI: 10.1038/s41538-024-00295-6

Comment by Dr. Krishna Kumari Challa on December 20, 2024 at 9:48am

Climate change could trigger more earthquakes, study suggests

A recent  study published in the journal Geology demonstrates that climate change can affect the frequency of earthquakes, adding to a small but growing body of evidence showing that climate can alter the seismic cycle.

Geoscientists analyzed the Sangre de Cristo Mountains in southern Colorado, a range with an active fault along its western edge. Their results indicate that the fault had been held in place under the weight of glaciers during the last ice age, and as the ice melted, slip along the fault increased. This suggests that earthquake activity along a fault could increase as glaciers recede.

Climate change is happening at a rate that is orders of magnitude faster than we see in the geologic record.

We see this in the rapid mountain glacial retreats in Alaska, the Himalayas and the Alps. In many of these regions, there are also active tectonics, and this work demonstrates that as climate change alters ice and water loads, tectonically active areas might see more frequent fault movements and earthquakes due to rapidly changing stress conditions.

It is well known that climate adjusts to seismic changes in the Earth's surface. The tectonic uplift of mountain ranges alters atmospheric circulation and rainfall, for example.

The Sangre de Cristo Mountains were covered with glaciers during the last ice age. Using remote-sensing and field data, the researchers reconstructed where the ice was, calculated the load that would have been pushing on the fault, and then measured displacement of the fault, or how much it had shifted.

The study found that fault slip rates have been five times faster since the last ice age than during the time the range was covered in glaciers. This research may preview how other glacier-adjacent faults will respond to a warming climate.

And this is compelling evidence. 

The research adds to our understanding of what drives earthquakes, which is important for hazard assessment. Faults in areas with rapidly retreating glaciers or evaporating large bodies of water may need to be monitored for increasing earthquake activity.

Cecilia Hurtado et al, Exploring the impact of deglaciation on fault slip in the Sangre de Cristo Mountains, Colorado, USA, Geology (2024). DOI: 10.1130/G52661.1

Comment by Dr. Krishna Kumari Challa on December 20, 2024 at 9:40am

This new  sunscreen uses TiO₂ nanoparticles to cool skin while blocking UV rays

Wearing sunscreen is important to protect your skin from the harmful effects of UV radiation but doesn't cool people off. However, a new formula, described in Nano Letters, protects against both UV light and heat from the sun using radiative cooling. The prototype sunblock kept human skin up to 11 degrees Fahrenheit (6 degrees Celsius) cooler than bare skin, or around 6 °F (3 °C) cooler than existing sunscreens.

Radiative cooling involves either reflecting or radiating heat away from something, cooling whatever's underneath. It is already used to create cooling fabrics and coatings that could both cool and heat homes, among other applications.

Some passive radiative cooling technologies rely on an ingredient called titanium dioxide (TiO2) because the whitish substance reflects heat. TiO2 particles are also used in mineral sunscreens to reflect UV light, but the particles aren't the right size to produce a cooling effect. So, researchers  wanted to tune the size of TiO2 nanoparticles to create a sunscreen that works both as a UV protector and a radiative cooler.

The team created their sunblock by combining six ingredients: TiO2 nanoparticles, water, ethanol, moisturizing cream, pigments, and a common silicone polymer used in cosmetics called polydimethylsiloxane. By carefully adjusting the sizes of the TiO2 nanoparticles, they produced a material that reflects both UV light and solar heat, imparting the cooling ability.

The new formulation demonstrated an SPF of about 50, water resistance and continued efficacy after 12 hours of simulated sunlight exposure with a xenon lamp. Additionally, when applied to both animal and human skin, the product didn't cause irritation.

In tests on people in a hot and humid outdoor environment, the new radiative cooling sunscreen was found to keep the participants' skin up to 10.8 °F (6.0 °C) cooler than bare skin, and up to 11.0 °F (6.1 °C) cooler than commercially available sunscreens. The formulation is inexpensive, costing only $0.92 for 10 grams of the mixture—on par with sunblocks already on the market.

Jiaqi Xu et al, High-Performance Radiative Cooling Sunscreen, Nano Letters (2024). DOI: 10.1021/acs.nanolett.4c04969

Comment by Dr. Krishna Kumari Challa on December 19, 2024 at 12:41pm

Your lifestyle may be aging your brain faster than you think

New research has found a relationship between lifestyle choices that affect dementia risk and early signs of aging in the brain.

Researchers discovered reduced white matter volume and an imbalance in electrical activity in the brains of participants whose lifestyle factors were linked to a higher risk of dementia.

It appeared factors like dietary habits, sleep patterns and physical activity levels, could already be affecting the brain before any signs of cognitive decline.

In the same way that sun safety choices can present on your skin and affect your future cancer risk, the researchers found a relationship between a person's lifestyle choices, their brain health, and their future dementia risk.

Even in very healthy older adults, higher modifiable dementia risk was connected to two major indicators of brain health—white and the brain's ability to balance its electrical activity.

It appears that the dementia risk of your daily choices is "painted" onto the canvas of your brain. The good news? The paint is still wet, and you're holding the brush.

Thomas Pace et al, Modifiable dementia risk associated with smaller white matter volume and altered 1/f aperiodic brain activity: cross-sectional insights from the LEISURE study, Age and Ageing (2024). DOI: 10.1093/ageing/afae243

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