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Comment by Dr. Krishna Kumari Challa on June 19, 2024 at 9:54am

Large wildfires create weather that favours more fire

A new  study shows soot from large wildfires in California traps sunlight, making days warmer and drier than they ought to be.

Many studies look at the effect of climate change on wildfires. However, this study sought to understand the reverse—whether large fires are also changing the climate.

Published in the journal Atmospheric Chemistry and Physics, the study found that large fires did have an effect. They made it hotter and drier than usual on the days the fires burned. The extra heat and aridity may then make conditions favorable for more fire.

It appears these fires are creating their own fire weather.

There are likely two reasons for this. One—soot traps heat, and two —the extra heat reduces humidity in the atmosphere, making it more difficult for clouds to form.

Fires emit smoke with black carbon, or soot. Since it is very dark, the soot absorbs sunlight more readily than bright or reflective things.

There are two types of aerosols: reflective and absorptive. Sulfate aerosols, which are byproducts of fossil fuel burning, are reflective and can cool the environment. These particles reflect the sun's energy back into space, keeping it out of the atmosphere.

Recent research points to an unfortunate byproduct of improving air quality by reducing sulfate aerosols. Since these particles have a cooling effect, removing them makes climate change more severe and leads to an increase in wildfires, especially in northern hemisphere forests.

Sulfate aerosols can also help make clouds brighter, more reflective, and more effective at cooling the planet.

The researchers note that the only way to prevent additional wildfires when cleaning up reflective sulfate air pollution is to simultaneously reduce emissions of greenhouse gases like carbon dioxide and methane.

Absorptive aerosols have the opposite effect. They trap light and heat in the atmosphere, which can raise temperatures. Black carbon, the most common aerosol emission from wildfires, is an absorbing aerosol. They not only directly make temperatures hotter, but indirectly as well by discouraging cloud formation and precipitation.

Fewer clouds mean less precipitation, which is problematic for drought-prone states.While some studies have shown an association between fires and brighter, more numerous clouds, this one did not.

James L. Gomez et al, California wildfire smoke contributes to a positive atmospheric temperature anomaly over the western United States, Atmospheric Chemistry and Physics (2024). DOI: 10.5194/acp-24-6937-2024

Comment by Dr. Krishna Kumari Challa on June 19, 2024 at 9:41am

Massive black holes—with masses over one hundred thousand times that of our sun—exist at the center of most galaxies, including the Milky Way.

These giant monsters usually are sleeping and not directly visible. In the case of SDSS1335+0728, scientists were able to observe the awakening of the massive black hole, which suddenly started to feast on gas available in its surroundings, becoming very bright.
This process has never been observed before.
Follow-up observations are still needed to rule out alternative explanations. Another possibility is that we are seeing an unusually slow tidal disruption event, or even a new phenomenon. If it is in fact a tidal disruption event, this would be the longest and faintest such event ever observed.

SDSS1335+0728: The awakening of a ∼ 10⁶M⊙ black hole, Astronomy & Astrophysics (2024). (PDF)

Part 2

Comment by Dr. Krishna Kumari Challa on June 19, 2024 at 9:39am

Astronomers see a massive black hole awaken in real time

In late 2019, the previously unremarkable galaxy SDSS1335+0728 suddenly started shining brighter than ever before. To understand why, astronomers have used data from several space and ground-based observatories, including the European Southern Observatory's Very Large Telescope (ESO's VLT), to track how the galaxy's brightness has varied. In a study out recently, they conclude that they are witnessing changes never seen before in a galaxy—likely the result of the sudden awakening of the massive black hole at its core.

Some phenomena, like supernova explosions or tidal disruption events—when a star gets too close to a black hole and is torn apart—can make galaxies suddenly light up. But these brightness variations typically last only a few dozen or, at most, a few hundreds of days. SDSS1335+0728 is still growing brighter today, more than four years after it was first seen to "switch on." Moreover, the variations detected in the galaxy, which is located 300 million light-years away in the constellation Virgo, are unlike any seen before, pointing astronomers towards a different explanation.

The team tried to understand these brightness variations using a combination of archival data and new observations from several facilities, including the X-shooter instrument on ESO's VLT in Chile's Atacama Desert. Comparing the data taken before and after December 2019, they found that SDSS1335+0728 is now radiating much more light at ultraviolet, optical, and infrared wavelengths. The galaxy also started emitting X-rays in February 2024.

The most tangible option to explain this phenomenon is that we are seeing how the core of the galaxy is beginning to show  activity. If so, this would be the first time that we see the activation of a massive black hole in real time.

Part 1

Comment by Dr. Krishna Kumari Challa on June 18, 2024 at 1:22pm

Bacterial batteries harvest energy from soil

Researchers developed a bacteria-powered battery which harvests energy from microorganisms in the soil to recharge itself, with a prototype already rolled out in Brazil.

Data on conditions in the field are crucial to help farmers make informed decisions and achieve the best possible yields, but powering the sensors that provide such data can be problematic.

Inventors of this technology say their low-cost, “always-on”, sustainable device – named Bactery – can help overcome some of these barriers.

The device, with an anticipated cost of around £25 per unit (US$32), operates by using bacteria present in the soil to generate electricity.

The technology makes use of microorganisms called electrigens which are naturally present in the soil and generate electrons when they consume organic matter.

One barrier to scaling, according to the researchers, is that the operating environment around the plant roots must be anaerobic – oxygen-free – to prevent the free electrons from attaching to the oxygen, which would make electricity generation unfeasible.

Therefore, he says, the system is designed to work in conditions where the plant roots are submerged in water, ensuring an oxygen-free environment and facilitating the transport of electrons.

There is a need for anaerobic conditions around one of the electrodes.

You can either install the technology in environments that accommodate this, or semi-engineer the environment to minimise the dependence on moisture.

According to Bactery, the technology promises an “install and forget” functionality and has a usable lifespan of over 25 years.

https://www.scidev.net/global/news/bacterial-batteries-harvest-ener...

Comment by Dr. Krishna Kumari Challa on June 18, 2024 at 12:51pm

How things appear in your mind’s eye

Picture a rose.

Most people can easily distinguish between that image in their mind’s eye and an actual rose flower. Now researchers say that they’ve worked out how the brain draws this distinction and where in the brain the process happens.

According to a study in monkeys, the key part of the brain is the primary visual cortex, which is also involved in vision. The authors found that neurons in this region displayed a different activity pattern for images conjured up from memory compared with that for real-time visual input. They conclude that the primary visual cortex is crucial for recalling images stored in memory.

The study in monkeys suggests that neurons there display a different activity pattern when images are conjured up from memory compared with real-time vision. Some researchers say that other areas, such as the prefrontal cortex, are more likely to be the seat of the ‘mind’s eye’. “There’s a possibility that the actual memory encoding is happening elsewhere, and that what you’re seeing in the primary visual cortex is the downstream consequences’, say the experts.

https://www.science.org/doi/10.1126/sciadv.adk3953

Comment by Dr. Krishna Kumari Challa on June 18, 2024 at 11:40am

No.	Fact	Opinion
1.	Verifiable and objective	Unverifiable and subjective
2.	Universal and doesn't vary from person to person	Can vary greatly among individuals
3.	Based on evidence	Based on beliefs or feelings
4.	Remains true irrespective of belief	Can change based on belief or new information
5.	Quantifiable and measurable	Not quantifiable or measurable
6.	Deals with reality and actual existence	Deals with personal interpretations and judgments
7.	Not influenced by personal emotions or biases	Often influenced by personal emotions or biases
8.	Can be proven true or false	Cannot be definitively proven true or false
9.	Can be replicated in investigations or experiments	Cannot be replicated as they are personal
10.	Can be accepted universally	Acceptance varies from person to person

Comment by Dr. Krishna Kumari Challa on June 18, 2024 at 9:34am

A 2016 study led by Steckler shows that these zones are now building stress, and could produce earthquakes comparable to the one 2,500 years ago. The last one of this size occurred in 1762, producing a deadly tsunami that traveled up the river to Dhaka. Another may have occurred around 1140 CE.

The 2016 study estimates that a modern recurrence of such a quake could affect 140 million people. Large earthquakes impact large areas and can have long-lasting economic, social and political effects.
The Ganges is not the only river facing such hazards. Others cradled in tectonically-active deltas include China's Yellow River; Myanmar's Irrawaddy; the Klamath, San Joaquin and Santa Clara rivers, which flow off the U.S. West Coast; and the Jordan, spanning the borders of Syria, Jordan, the Palestinian West Bank and Israel.
Cascading hazards of a major Bengal basin earthquake and abrupt avulsion of the Ganges River, Nature Communications (2024). DOI: 10.1038/s41467-024-47786-4
Part 3
**

Comment by Dr. Krishna Kumari Challa on June 18, 2024 at 9:33am

In satellite imagery, the authors of the new study spotted what they say was probably the former main channel of the river, some 100 kilometers south of the Bangladeshi capital of Dhaka. This is a low-lying area about 1.5 kilometers wide that can be found intermittently for some 100 kilometers more or less parallel to the current river course. Filled with mud, it frequently floods, and is used mainly for rice cultivation.

Chamberlain and other researchers were exploring this area in 2018 when they came across a freshly dug excavation for a pond that had not yet been filled with water.

On one flank, they spotted distinct vertical dikes of light-colored sand cutting up through horizontal layers of mud. This is a well-known feature created by earthquakes: In such watery areas, sustained shaking can pressurize buried layers of sand and inject them upward through overlying mud. The result: literal sand volcanoes, which can erupt at the surface. Called seismites, here, they were 30 or 40 centimeters wide, cutting up through 3 or 4 meters of mud.

Further investigation showed the seismites were oriented in a systematic pattern, suggesting they were all created at the same time. Chemical analyses of sand grains and particles of mud showed that the eruptions and the abandonment and infilling of the channel both took place about 2,500 years ago.

Furthermore, there was a similar site some 85 kilometers downstream in the old channel that had filled in with mud at the same time. The authors' conclusion: This was a big, sudden avulsion triggered by an earthquake, estimated to be magnitude 7 or 8.
The quake could have had one of two possible sources, they say. One is a subduction zone to the south and east, where a huge plate of oceanic crust is shoving itself under Bangladesh, Myanmar and northeastern India. Or it could have come from giant splay faults at the foot of the Himalayas to the north, which are slowly rising because the Indian subcontinent is slowly colliding with the rest of Asia.
Part 2

Comment by Dr. Krishna Kumari Challa on June 18, 2024 at 9:32am

An earthquake changed the course of the Ganges: Could it happen again?

A major earthquake 2,500 years ago caused one of the largest rivers on Earth to abruptly change course, according to a new study. The previously undocumented quake rerouted the main channel of the Ganges River in what is now densely populated Bangladesh, which remains vulnerable to big quakes. The study was published in the journal Nature Communications.

Scientists have documented many river-course changes, called avulsions, including some in response to earthquakes.

It was not previously confirmed that earthquakes could drive avulsion in deltas, especially for an immense river like the Ganges.

The Ganges rises in the Himalayas and flows for some 1,600 miles, eventually combining with other major rivers including the Brahmaputra and the Meghna to form a labyrinth of waterways that empty into a wide stretch of the Bay of Bengal spanning Bangladesh and India. Together, they form the world's second-largest river system as measured by discharge. (The Amazon is first.)

Like other rivers that run through major deltas, the Ganges periodically undergoes minor or major course changes without any help from earthquakes. Sediments washed from upstream settle and build up in the channel, until eventually the river bed grows subtly higher than the surrounding flood plain.

At some point, the water breaks through and begins constructing a new path for itself. But this does not generally happen all at once—it may take successive floods over years or decades. An earthquake-related avulsion, on the other hand, can occur more or less instantaneously.

Part 1

Comment by Dr. Krishna Kumari Challa on June 18, 2024 at 9:08am

A new look at why old age is linked to severe, even fatal COVID

A longstanding question has nagged the COVID battle for more than four years: Why does the infection cause severe disease in older people?

Ever since the beginning of the pandemic in 2020, it has been abundantly clear that older adults are at substantial risk of severe, even fatal COVID. Yet, the underlying mechanisms for their susceptibility were not always clear despite studies that took co-morbidities into account, like diabetes, heart and lung disorders, and other chronic vagaries of age that can worsen a bout with an infectious disease.

To date, scientists have blamed a dysregulated immune system, an age-related affinity toward excessive blood clotting, and an overall decline in the key soldiers of the adaptive immune system, T and B cells, to explain increased risks for severe COVID in the aging population. And while all of those factors may play a role, an inevitable question looms large: Why?

A new multicenter clinical study, reported in Science Translational Medicine, has provided comprehensive answers and peels away some of the mystery surrounding poor outcomes for older people. 

Results from the new tests bore novel data and a new level of understanding.

Older age correlated with increased SARS-CoV-2 viral abundance upon hospital admission, delayed viral clearance, and increased type I interferon gene expression in both the blood and upper airway.

Researchers also observed age-dependent up-regulation of innate immune signaling pathways and down-regulation of adaptive immune signaling pathways.

The innate immune system's monocyte production escalated while naïve T and B cells of the adaptive immune system were low.

Unlike younger patients, older ones also displayed more active innate immune pathways and a persistent rise in pro-inflammatory genes and cytokines, suggesting that advancing age may disrupt the body's ability to turn off the inflammatory response. Additionally, biomarkers of disease severity, such as interleukin-6, were the most extreme in the oldest patients. Together, these data provide insight into why age is a major risk factor for severe COVID, the research team concluded.

The study finds that aging is associated with impaired viral clearance, dysregulated immune signaling, and persistent and potentially pathologic activation of pro-inflammatory genes and proteins.

These differences raise the possibility that older adults with severe COVID-19 may respond differently, and perhaps more favorably, to immunomodulatory therapies directed at certain inflammatory cytokines.

 Hoang Van Phan et al, Host-microbe multiomic profiling reveals age-dependent immune dysregulation associated with COVID-19 immunopathology, Science Translational Medicine (2024). DOI: 10.1126/scitranslmed.adj5154

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