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Comment by Dr. Krishna Kumari Challa on November 21, 2023 at 12:31pm

What is a sonar pulse and how can it injure humans under water?
Light doesn't travel well underwater—even in clear waters, you can see perhaps some tens of meters. Sound, however, travels very well and far underwater. This is because water is much denser than air, and so can respond faster and better to acoustic pressure waves—sound waves.

Because of these properties, ships use sonar to navigate through the ocean and to "see" underwater. The word "sonar" stands for sound navigation and ranging.

Sonar equipment sends out short acoustic (sound) pulses or pings and then analyzes the echoes. Depending on the timing, amplitude, phase, and direction of the echoes the equipment receives, you can tell what's underwater—the seafloor, canyon walls, coral, fishes, and of course, ships and submarines.

Most vessels—from small, private boats to large commercial tankers—use sonar. However, compared to your off-the-shelf sonar used for finding fish, navy sonars are stronger.
The effects of sonar on divers
We don't hear well underwater—no surprise since we've evolved to live on land. Having said that, you would hear a sonar sound underwater (a mid-to-high pitch noise) and would know you've been exposed.
When it comes to naval sonars, human divers have rated the sound as "unpleasant to severe" at levels of roughly 150dB re 1 µPa (decibel relative to a reference pressure of one micro pascal, the standard reference for underwater sound). This would be, perhaps, very roughly 10km away from a military sonar. Note that we can't compare sound exposure under water to what we'd receive through the air because there are too many physical differences between the two.

Human tolerance limits are roughly 180dB re one µPa, which would be around 500m from military sonar. At such levels, humans might experience dizziness, disorientation, temporary memory and concentration impacts, or temporary hearing loss.
At higher received levels, closer ranges, or longer exposures, you might see more severe physiological or health impacts. In extreme cases, in particular, for impulsive, sudden sound (which sonar is not), sound can cause damage to tissues and organs.
What does sonar do to marine animals?
Some of the information on what noise might do to humans underwater comes from studies and observations of animals.

While they typically don't have outer ears (except for sea lions), marine mammals have inner ears that function similarly to ours. They can receive hearing damage from noise, just like we do. This might be temporary, like the ringing ears or reduced sensitivity you might experience after a loud concert, or it can be permanent.

Marine mammals living in a dark ocean rely on sound and hearing to a greater extent than your average human. They use sound to navigate, hunt, communicate with each other and to find mates. Toothed whales and dolphins have evolved a biological echo sounder or biosonar, which sends out series of clicks and listens for echoes. So, interfering with their sounds or impacting their hearing can disrupt critical behaviors.

Finally, sound may also impact non-mammalian fauna, such as fishes, which rely on acoustics rather than vision for many of their life functions.

https://theconversation.com/what-is-a-sonar-pulse-and-how-can-it-in...

Comment by Dr. Krishna Kumari Challa on November 21, 2023 at 12:06pm

World's richest 1% emit as much carbon as bottom two-thirds: report

The richest one percent of the global population are responsible for the same amount of carbon emissions as the world's poorest two-thirds, or five billion people, according to an analysis published Sunday by the nonprofit Oxfam International.

While fighting the climate crisis is a shared challenge, not everyone is equally responsible and government policies must be tailored accordingly, according to the report.

It says, the richer you are, the easier it is to cut both your personal and your investment emissions. You don't need that third car, or that fourth holiday, or you don't need to be invested in the cement industry." 

Climate Equality: A Planet for the 99%", was based on research compiled by the Stockholm Environment Institute (SEI) and it examined the consumption emissions associated with different income groups up to the year 2019.
Among the key findings of this study are that the richest one percent globally—77 million people—were responsible for 16 percent of global emissions related to their consumption.

That is the same share as the bottom 66 percent of the global population by income, or 5.11 billion people.
Source: 2023 AFP

Comment by Dr. Krishna Kumari Challa on November 21, 2023 at 11:17am

Levels of this flavanol can vary dramatically in red wine

Quercetin is produced by the grapes in response to sunlight. If you grow grapes with the clusters exposed, such as they do in the Napa Valley for their cabernets, you get much higher levels of quercetin. In some cases, it can be four to five times higher.

Levels of quercetin can also differ depending on how the wine is made, including skin contact during fermentation, fining processes and aging.

Scientists are testing this hypothesis  now .

 Inhibition of ALDH2 by Quercetin Glucuronide Suggests a New Hypothesis to Explain Red Wine Headaches, Scientific Reports (2023).

Part 2

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Comment by Dr. Krishna Kumari Challa on November 21, 2023 at 11:12am

Why does even a small amount of red wine give some people headaches?

 For some people, drinking red wine even in small amounts causes a headache. Typically, a "red wine headache" can occur within 30 minutes to three hours after drinking as little as a small glass of wine.

In a new study, scientists examined why this happens—even to people who don't get headaches when drinking small amounts of other alcoholic beverages. Researchers think that a flavanol found naturally in red wines can interfere with the proper metabolism of alcohol and can lead to a headache. The study was published in the journal Scientific Reports.

This flavanol is called quercetin and it is naturally present in all kinds of fruits and vegetables, including grapes. It's considered a healthy antioxidant and is even available in supplement form. But when metabolized with alcohol, it can be problematic.

When it gets in your bloodstream, your body converts it to a different form called quercetin glucuronide. In that form, it blocks the metabolism of alcohol. As a result, people can end up accumulating the toxin acetaldehyde. Acetaldehyde is a well-known toxin, irritant and inflammatory substance. Researchers know that high levels of acetaldehyde can cause facial flushing, headache and nausea.

The medication disulfiram prescribed to alcoholics to prevent them from drinking causes these same symptoms. That's because the drug also causes the toxin to build up in the body when normally an enzyme in the body would break it down. About 40% of the East Asian population also has an enzyme that doesn't work very well, allowing acetaldehyde to build up in their system.

 When susceptible people consume wine with even modest amounts of quercetin, they develop headaches, particularly if they have a preexisting migraine or another primary headache condition.

Part 1

Comment by Dr. Krishna Kumari Challa on November 20, 2023 at 11:13am

Brightest flash ever disturbed Earth's atmosphere last year

Last year the brightest flash of light ever seen in the night sky disturbed Earth's upper atmosphere in a way that has never before detected before.

A massive burst of gamma rays from an enormous cosmic explosion around two billion light years away arrived at Earth on October 9, 2022, lighting up telescopes around the world.

Quickly nicknamed the "BOAT"—for Brightest Of All Time—the flash lasted just seven minutes but its afterglow was visible to amateur astronomers for seven hours.

The flash activated lightning detectors in India and triggered instruments that normally study explosions on the sun called solar flares. It also affected long wave radio communications in the lower ionosphere, a section of Earth's upper atmosphere around 60 to 350 kilometers (37 to 217 miles) above the surface. The BOAT also affected the upper ionosphere—the very first time a gamma-ray burst has been observed in this section of the atmosphere.

From 350 to 950 kilometers above Earth, near the edge of the space, the upper ionosphere is where radiation from the sun turns into charged particles that form an important electric field.

Researchers found a shape in the electric field that had never been observed before.

The research would help scientists understand the potential threat that other gamma-ray bursts could pose in the future. The worst-case scenario would be if such a powerful blast came from much closer to home—say, within our own Milky Way galaxy. That could "completely erase" Earth's ozone layer.

This would expose everything on the surface to the full might of the sun's ultraviolet radiation, potentially wiping out life on Earth. There has previously been speculation that past gamma-ray bursts could have caused ancient mass extinction events.

But It is also possible that the ionosphere would absorb all the gamma rays and "nothing would happen" to those of us on the ground.

The blast came from the direction of the constellation Sagitta and traveled an estimated 1.9 billion years to reach Earth. It is now 2.4 billion light years away because of the expansion of the universe. On average, more than one gamma-ray-burst reaches Earth every day. But one with the brightness of the BOAT is estimated to come around once every 10,000 years.

Mirko Piersanti, Evidence of an upper ionospheric electric field perturbation correlated with a gamma ray burst, Nature Communications (2023). DOI: 10.1038/s41467-023-42551-5. www.nature.com/articles/s41467-023-42551-5

Comment by Dr. Krishna Kumari Challa on November 20, 2023 at 10:26am

Early-life stress changes more genes in the brain than a head injury

A surprising thing happened when researchers began exploring whether early-life stress compounds the effects of a childhood head injury on health and behavior later in life. In an animal study, stress changed the activation level of many more genes in the brain than were changed by a bump to the head.

It's already known that head injuries are common in young kids, especially from falling, and can be linked to mood disorders and social difficulties that emerge later in life. Adverse childhood experiences are also very common, and can raise risk for disease, mental illness and substance misuse in adulthood.

Researchers found many, many, many more genes were differentially expressed as a result of their early life stress manipulation than their traumatic brain injury manipulation in animals.

Stress is really powerful, and we shouldn't understate the impact of early life stress on the developing brain, according to them. 

The research poster was presented Nov. 12, 2023 at Neuroscience 2023, the annual meeting of the Society for Neuroscience.

https://www.sfn.org/meetings/neuroscience-2023

Comment by Dr. Krishna Kumari Challa on November 20, 2023 at 10:19am

(a) System dynamics associated with three major groups of Anthropocene traps, global traps, technology traps and structural traps (including temporal and connectivity traps). Two reinforcing feedback loops are indicated with R and interactions between dynamics across groups oftraps are indicated with colored superscript letters (color of causal node) and stippled lined arrows. Credit: Philosophical Transactions of the Royal Society B

Part 3

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Comment by Dr. Krishna Kumari Challa on November 20, 2023 at 10:18am

The simplification of agricultural systems is an example of such a trap. Relying on a few highly productive crops such as wheat, rice, maize, and soya, has meant that calories produced have skyrocketed over the past century. But it also meant that the food system has become very vulnerable to environmental change, such as weather extremes, or new diseases.

Of the 14 evolutionary traps, 12 are in an advanced state, meaning that humankind is on the verge of getting stuck to a degree where it becomes very difficult to get out. What's more, societies are continuing to move in the wrong direction in 10 of these 14.

Alarmingly, these evolutionary traps tend to reinforce each other. If societies get stuck in one dead end, they are more likely to get stuck in others as well. The two dead ends which currently are less advanced are the autonomy of technology—AI and robotics—and a loss of social capital through digitalization.

The new assessment also looks into why societies struggle so hard to move out of these traps.

The evolutionary forces that created the Anthropocene do not work well at the global level. In today's global systems, social and environmental problems grow in places that seem distant to the societies that could prevent them. Also, addressing them often requires global collaboration on a scale that many evolutionary forces often do not align well with.

This does not mean that humanity is doomed to fail, argue the researchers. But we must start to transform our societies actively. So far, the Anthropocene has to a large extent been an unconscious byproduct of other evolutionary processes.

"It's time for humans to become aware of the new reality and to collectively move where we want to as a species. We have the capability to do that and are already seeing signs of such movements. Our creativity, and our power to innovate and collaborate equip us with the perfect tools to actively design our future. We can break out of dead ends and business-as-usual, but for that, we must nurture the capacity for collective human agency and design settings where it can flourish.

A very simple thing that everybody can do is to engage more in nature and society while also learning about both the positive and negative global consequences of our own local actions.

 Peter Søgaard Jørgensen et al, Evolution of the polycrisis: Anthropocene traps that challenge global sustainability, Philosophical Transactions of the Royal Society of London (B ) (2023). DOI: 10.1098/rstb.2022.0261

Part 2

Comment by Dr. Krishna Kumari Challa on November 20, 2023 at 10:15am

New research maps 14 potential evolutionary dead ends for humanity and ways to avoid them

For the first time, scientists have used the concept of evolutionary traps on human societies at large. They find that humankind risks getting stuck in 14 evolutionary dead ends, ranging from global climate tipping points to misaligned artificial intelligence, chemical pollution, and accelerating infectious diseases.

The evolution of humankind has been an extraordinary success story. But the Anthropocene—the proposed geological epoch shaped by us humans—is showing more and more cracks. Multiple global crises, such as the COVID-19 pandemic, climate change, food insecurity, financial crises, and conflicts have started to occur simultaneously in something which scientists refer to as a polycrisis.

Humans are incredibly creative as a species. We are able to innovate and adapt to many circumstances and can cooperate on surprisingly large scales. But these capabilities turn out to have unintentional consequences. Simply speaking, you could say that the human species has been too successful and, in some ways, too smart for its own future good.

The  new study published as part of a larger assessment in the journal Philosophical Transactions of the Royal Society B. The assessment gathers insights from a wide range of different scientific disciplines across the natural and social sciences and humanities, to understand how the Anthropocene evolved and how global sustainability can continue to evolve in the future.

The new study shows how humanity could get stuck in "evolutionary traps"—dead ends that occur from initially successful innovations. In a first scoping effort, they identify 14 of these, including the simplification of agriculture, economic growth that does not deliver benefits for humans or the environment, the instability of global cooperation, climate tipping points, and artificial intelligence.

Evolutionary traps are a well-known concept in the animal world. Just like many insects are attracted by light, an evolutionary reflex that can get them killed in the modern world, humankind is at risk of responding to new phenomena in harmful ways.

Part 1

Comment by Dr. Krishna Kumari Challa on November 19, 2023 at 11:45am

But on other planets, things are a little less spectacular, at least to human eyes. The nightglow on Venus is infrared. On Jupiter, the glow is more ultraviolet (and apparently variable).

On Mars, infrared and ultraviolet nightglow have been seen. Scientists have even seen dayglow caused by the atmospheric absorption and release of energy from solar radiation in the visible spectrum on Mars (although you wouldn't be able to see it yourself, as a Mars explorer; daylight is simply too bright).

But "No nightglow spectrum has been observed so far in the visible domain," the researchers write. "Scattered solar light hinders such measurements from Earth's ground and no space-borne instrument has observed the Mars visible nightglow."
Between altitudes of 40 and 60 kilometers (25 to 37 miles), visible nightglow was spotted at the south pole during its Martian winter.

This, the researchers say, is the result of oxygen atoms transported from the sunny Martian day combining into dioxygen (O2), emitting a glow in the process – one bright enough to be seen from the ground.

This O₂ nightglow should be observable from a Martian orbiter as well as from the Martian surface with the naked eye under clear sky conditions," the researchers write.

https://www.nature.com/articles/s41550-023-02104-8

Part 2

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