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Comment by Dr. Krishna Kumari Challa on September 3, 2024 at 9:29am

When the rice fields were flooded, and arsenic was taken up, the researchers noticed methanogenesis happening, which is when organisms in the soil produce the potent greenhouse gas methane and emit it into the atmosphere. Meanwhile, the excess water reduced sulfate in the soil to sulfide, causing cadmium to precipitate out with the sulfide.

When they dried the soil out, the researchers decreased the levels of arsenic and methane. Sulfide in the soil was oxidized and became sulfate, which is no longer a solid phase, allowing cadmium to easily filter through and escape into the plant easily.

By drying out the soil, you can put the brakes on the microorganisms that breathe with iron oxides and with arsenic.

Then we actually increase the amount of cadmium because we oxidize the sulfide to sulfate. When it becomes sulfate, it's no longer a solid phase with the cadmium, and the cadmium can then be free.

Drying the soil out introduced oxygen into the soil pores, which slowed down the microorganisms that dissolve iron oxides and create methane and changed the chemistry.

Once you introduce oxygen, the iron oxides that dissolved are solid again.

What they found—one metal or metalloid increasing with the other decreasing depending on the level of moisture in the soil—presents a bit of a puzzle.

 researchers have also reported, in a review paper they published in the journal GeoHealth, that producers are willing to take any action needed to reduce levels of metals in their crops, but they need incentives, testing and education in order to do so.

Matt A. Limmer et al, Controlling exposure to As and Cd from rice via irrigation management, Environmental Geochemistry and Health (2024). DOI: 10.1007/s10653-024-02116-x

Angelia L. Seyfferth et al, Mitigating Toxic Metal Exposure Through Leafy Greens: A Comprehensive Review Contrasting Cadmium and Lead in Spinach, GeoHealth (2024). DOI: 10.1029/2024GH001081

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Comment by Dr. Krishna Kumari Challa on September 3, 2024 at 9:26am

Curbing toxic metals in spinach and rice crops grown for baby food

Rice and spinach are staples for babies' and young children's diets, but toxic metals and metalloids found in those foods can cause severe health impacts.

In particular, heavy metals such as cadmium, lead, mercury, and metalloid arsenic could delay brain development in babies and young children.

In new research published in the academic journal Environmental Geochemistry and Health,  scientists have found that flooded rice fields tend to contain higher amounts of arsenic and lower amounts of cadmium. The drier those rice fields are, the lower the amounts of arsenic and the higher the amounts of cadmium. However, the higher cadmium is lower than the existing threshold for adverse health effects.

The findings could help establish a course of action for decreasing the levels of these contaminants in foods typically eaten by infants and children.

Crops such as corn, soybeans and wheat are grown in soils that are not very wet. So farmers water them to make sure the plants get the nutrients they need to grow, but never enough to fully flood them.

In contrast, rice is often grown in very wet, flooded soils. Oxygen that would normally reside in tiny pores in the soil gets lost very quickly and is replaced by water. The limited oxygen shifts the microorganisms in the soil, and those microorganisms start breathing with iron oxide minerals that give the soil a rusty orange color.

Arsenic likes to stick really tightly onto those iron oxides.

When the iron oxides are used by these organisms to breathe, they go from a solid mineral to a solution phase. You essentially dissolve them, and when you dissolve them, the arsenic that's stuck onto them goes into the water.  Once the arsenic is in the water, it can easily be absorbed by the rice roots and transported into the grain.

Scientists are trying to find an optimal irrigation management that minimized both arsenic and cadmium simultaneously.

Once they harvested the grain  scientists analyzed the amount of arsenic and cadmium in it and they  found that the more flooded the field, the more arsenic and less cadmium accumulated in the rice. By contrast, the drier the field, the more cadmium and less arsenic accumulated.

But, even under those drier conditions when there was more cadmium, the concentrations of cadmium in the grain were not of concern for human health.

Part 1

Comment by Dr. Krishna Kumari Challa on September 3, 2024 at 9:12am

Our latest results show no signs of dark matter. However, they let us rule out a lot of possibilities.

We found no traces of particles with masses above 1.6 × 10–26 kilograms, which is about 10-times as heavy as a proton.

These results are based on 280 days' worth of observations from the detector. Eventually, we aim to collect 1,000 days' worth—which will let us search for even more elusive potential dark matter particles.

If we're lucky, we might find dark matter turns up in the new data. If not, we have already begun to make plans for a next generation dark matter experiment. The XLZD (XENON-LUX-ZEPLIN-DARWIN) consortium is aiming to build a detector almost 10-times bigger that would allow us to trawl through even more of the space where these ubiquitous yet elusive particles may be hiding.

This article is republished from The Conversation under a Creative Commons license. Read the original article.

Part 3

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Comment by Dr. Krishna Kumari Challa on September 3, 2024 at 9:12am

The LZ experiment is located in an old goldmine about 1,500 meters below ground in South Dakota in the US. Placing the experiment deep underground helps to cut out as much background radiation as possible.

The experiment consists of a large double-walled tank filled with seven tons of liquid xenon, a noble gas chilled down to a temperature of 175 kelvin (–98°C).

If a dark matter particle smacks into a xenon nucleus, it should give off a tiny flash of light. Our detector has 494 light sensors to detect these flashes.
Of course, dark matter particles aren't the only things that can create these flashes. There is still some background radiation from the surroundings and even the materials of the tank and detectors themselves.

A big part of figuring out whether we are seeing signs of dark matter is disentangling this background radiation from anything more exotic. To do this, we make detailed simulations of the results we would expect to see with and without dark matter.

These simulations have been the focus of much of my part in the experiment, which began when I started my Ph.D. in 2015. I also developed detector monitoring sensors and was responsible for the integration and commissioning of the central detector underground, which began collecting data in 2021.
Part 2

Comment by Dr. Krishna Kumari Challa on September 3, 2024 at 9:11am

85% of the matter in the universe is missing: But scientists are getting closer to finding it

Most of the matter in the universe is missing. Scientists  think around 85% of the matter in the cosmos is made of invisible dark matter, which has only been detected indirectly by its gravitational effects on its surroundings.

A team of some 250 scientists from around the world working on a dark matter experiment called LUX-ZEPLIN (or LZ)—report our latest findings from the long quest to discover exactly what this dark matter is made of.

 They have not yet found the elusive particles we believe dark matter consists of, but they have set the tightest limits yet on their properties. They have also shown our detector is working as expected—and should produce even better results in the future.

When astronomers look at the universe, they see evidence that the visible matter of stars, gas and galaxies is not all there is. Many phenomena, such as how fast galaxies spin and the pattern of the residual glow of the Big Bang, can only be explained by the presence of large amounts of some invisible substance—dark matter.

So what is this dark matter made of? We currently don't know of any kind of particle that could explain these astronomical observations.

There are dozens of theories that aim to explain dark matter observations, ranging from exotic unknown particles to tiny black holes or fundamental changes to our theory of gravity. However, none of them has yet been proven correct.
One of the most popular theories suggests dark matter is made up of so-called "weakly interacting massive particles" (or WIMPs). These relatively heavy particles could cause the observed gravitational effects and also—very rarely—interact with ordinary matter.

How would we know if this theory is correct? Well, we think these particles must be streaming through Earth all the time. For the most part, they will pass through without interacting with anything, but every so often a WIMP might crash directly into the nucleus of an atom—and these collisions are what we are trying to spot.
Part 1

Comment by Dr. Krishna Kumari Challa on September 3, 2024 at 9:06am

In essence, the quartz acts like a natural battery, with gold as the electrode, slowly accumulating more gold with each seismic event.

This process could explain why large gold nuggets are so often associated with quartz veins formed in earthquake-related deposits.

This new understanding of gold nugget formation not only sheds light on a longstanding geological mystery but also highlights the interrelationship between Earth's physical and chemical processes.

Nature Geoscience (2024). www.nature.com/articles/s41561-024-01514-1

Part 2

Comment by Dr. Krishna Kumari Challa on September 3, 2024 at 9:05am

Electricity generated by earthquakes might be the secret behind giant gold nuggets

Scientists have long been fascinated by the formation of gold nuggets, often found nestled within quartz veins. New research led by Monash University geologists suggests that the process might be even more electrifying than we previously thought—literally.

Gold nuggets, prized for their rarity and beauty, have been at the heart of gold rushes for centuries.

The standard explanation by Geologists till now is that gold precipitates from hot, water-rich fluids as they flow through cracks in the Earth's crust. As these fluids cool or undergo chemical changes, gold separates out and becomes trapped in quartz veins.

While this theory is widely accepted, it doesn't fully explain the formation of large gold nuggets, especially considering that the concentration of gold in these fluids is extremely low.

The present research team tested a new concept, piezoelectricity. Quartz, the mineral that typically hosts these gold deposits, has a unique property called piezoelectricity—it generates an electric charge when subjected to stress. This phenomenon is already familiar to us in everyday items like quartz watches and BBQ lighters, where a small mechanical force creates a significant voltage. What if the stress from earthquakes could do something similar within the Earth?

To test this hypothesis, researchers conducted an experiment designed to replicate the conditions quartz might experience during an earthquake. They submerged quartz crystals in a gold-rich fluid and applied stress using a motor to simulate the shaking of an earthquake. After the experiment, the quartz samples were examined under a microscope to see if any gold had been deposited.

And the results were stunning!

The stressed quartz not only electrochemically deposited gold onto its surface, but it also formed and accumulated gold nanoparticles. Remarkably, the gold had a tendency to deposit on existing gold grains rather than forming new ones.

This is because, while quartz is an electrical insulator, gold is a conductor.

Once some gold is deposited, it becomes a focal point for further growth, effectively "plating" the gold grains with more gold.

This discovery provides a plausible explanation for the formation of large gold nuggets in quartz veins.

As the quartz is repeatedly stressed by earthquakes, it generates piezoelectric voltages that can reduce dissolved gold from the surrounding fluid, causing it to deposit.

Over time, this process could lead to the formation of significant gold accumulations, ultimately producing the massive nuggets that have captivated treasure hunters and geologists alike.

Part 1

Comment by Dr. Krishna Kumari Challa on September 3, 2024 at 8:58am

How hunger influences aversive learning in fruit flies

Internal states that animals experience while they are thirsty, hungry, sleepy or aggressive have been found to be linked with the combined activity of various neuromodulators and neurotransmitters. These chemical messengers can drastically change the excitability and functional connectivity of neurons, which in turn plays a role in shaping the animals' behaviour.

Past studies on Drosophila (small fruit flies) showed that energy homeostasis in these insects is regulated by various neurohormones/modulators, which impact their physiology and behavior in different ways. These include insulin-like peptides (dILPs) and adipokinetic hormone (AKH), hormones with the same functions as insulin and glucagon in mammals, respectively.

Researchers recently carried out a study investigating how these hunger-associated neurohormones influence the learning of associations between stimuli and unpleasant or negative outcomes (i.e., aversive learning) in fruit flies. Their paper, published in Neuron, shows that the hormone AKH plays a key role in modulating aversive reinforcement learning.  

Hungry animals need compensatory mechanisms to maintain flexible brain function, while modulation reconfigures circuits to prioritize resource seeking.

In Drosophila, hunger inhibits aversively reinforcing dopaminergic neurons (DANs) to permit the expression of food-seeking memories. Multitasking the reinforcement system for motivation potentially undermines aversive learning.

Aversive learning is an evolutionary process through which animals start to associate specific stimuli with unpleasant outcomes, after repeated negative experiences following the exposure to these stimuli. This often results in behaviors aimed at trying to avoid the stimulus and the experiences associated with it.

The researchers found that chronic hunger mildly enhances aversive learning and that satiated-baseline and hunger-enhanced learning require endocrine adipokinetic hormone (AKH) signaling.

The researchers' experiments revealed that AKH, the fly equivalent of glucagon, sets baseline and hunger-enhanced levels of aversive learning, acting through specific neurons that release the neurotransmitter octopamine. This neurotransmitter modulates the inputs sent to dopaminergic neurons involved in reinforcement aversive learning.

The findings of this recent study contribute to the understanding of how hunger affects aversive learning in Drosophila, specifically highlighting the key role of the neurohormone AKH. In the future, it could inspire further research aimed at validating the patterns observed by the researchers across other animal models.

Eleonora Meschi et al, Compensatory enhancement of input maintains aversive dopaminergic reinforcement in hungry Drosophila, Neuron (2024). DOI: 10.1016/j.neuron.2024.04.035

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Comment by Dr. Krishna Kumari Challa on September 2, 2024 at 8:31am

Study finds people are consistently and confidently wrong about those with opposing views

Despite being highly confident that they can understand the minds of people with opposing viewpoints, the assumptions humans make about others are often wrong, according to new research from the Institute of Psychiatry, Psychology & Neuroscience (IoPPN).

"Poorer representation of minds underpins less accurate mental state inference for out-groups" was published in Scientific Reports. The research explores the psychology behind why people come to the wrong conclusions about others, and suggests how society could start to change that.

Analysis of the data found that, even though participants were prepared to seek out as much—and often more—information about someone they disagreed with, their predictions were consistently incorrect, even after receiving further information about them.

Participants demonstrated a high degree of confidence in their answers, suggesting that participants thought they had a good understanding of the people in their out-group, despite this not being the case. In comparison, participants could consistently make accurate predictions about those in their in-group with less information.

The study shows that people have a good understanding of people who are similar to themselves and their confidence in their understanding is well-placed. However, our understanding of people with different views to our own is demonstrably poor. The more confident we are that we can understand them, the more likely it is that we are wrong. People have poor awareness of their inability to understand people that differ from themselves.

There are clear consequences to this lack of awareness, and we have seen countless real-world examples.

These misconceptions are often fueled by disinformation on social media or echoed back to them by others within their in-group.

While there is no quick fix in a real-world setting, if everyone interacted with a more diverse group of people, talked directly to them and got to know them, it's likely we would understand each other better. Conversations with people who hold different beliefs could help challenge our incorrect assumptions about each other.

Now do you understand why you think scientists are wrong? Because they see and talk about reality, not about your imaginations.

Bryony Payne et al, Poorer representation of minds underpins less accurate mental state inference for out-groups, Scientific Reports (2024). DOI: 10.1038/s41598-024-67311-3

Comment by Dr. Krishna Kumari Challa on September 2, 2024 at 8:08am

This finding challenges the traditional view of educational achievement as determined largely by intelligence. Instead, the study suggests that a child's emotional and behavioral makeup, influenced by both genes and environment, plays a crucial role in their educational journey.

While genetics undoubtedly contributes to non-cognitive skills, the study also emphasizes the importance of environment. By comparing siblings, researchers were able to isolate the impact of shared family environment from genetic factors.

The researchers found that while family-wide processes play a significant role, the increasing influence of non-cognitive genetics on academic achievement remained evident even within families. This suggests that children may actively shape their own learning experiences based on their personality, dispositions, and abilities, creating a feedback loop that reinforces their strengths.

The findings of this study have profound implications for education. By recognizing the critical role of non-cognitive skills, schools can develop targeted interventions to support students' emotional and social development alongside their academic learning.

Education system world wide has traditionally focused on cognitive development. It's time to rebalance that focus and give equal importance to nurturing non-cognitive skills. By doing so, we can create a more inclusive and effective learning environment for all students, say the researchers.

Genetic associations between noncognitive skills and academic achievement over development, Nature Human Behaviour (2024). DOI: 10.1038/s41562-024-01967-9

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