Comment

Comment by Dr. Krishna Kumari Challa on May 28, 2024 at 6:33am

Unfortunately, such light can also be a signature of a lot of other things, such as a disk of gas and dust, or disks of comets and other debris. But the seven promising candidates aren't obviously due to a disk, as they weren't good fits to disk models.

It is worth noting there is another signature of Dyson sphere: that visible light from the star dips as the megastructure passes in front of it. Such a signature has been found before. There was a lot of excitement about Tabby's star, or Kic 8462852, which showed many really unusual dips in its light that could be due to an alien megastructure.

It almost certainly isn't an alien megastructure. A variety of natural explanations have been proposed, such as clouds of comets passing through a dust cloud. But it is an odd observation. An obvious follow up on the seven candidates would be to look for this signature as well.
The case against Dyson spheres
Dyson spheres may well not even exist, however. I think they are unlikely to be there. That's not to say they couldn't exist, rather that any civilization capable of building them would probably not need to (unless it was some mega art project).

Dyson's reasoning for considering such megastructures assumed that advanced civilizations would have vast power requirements. Around the same time, astronomer Nikolai Kardashev proposed a scale on which to rate the advancement of civilizations, which was based almost entirely on their power consumption.

In the 1960s, this sort of made sense. Looking back over history, humanity had just kept exponentially increasing its power use as technology advanced and the number of people increased, so they just extrapolated this ever-expanding need into the future.

Part 2

Comment by Dr. Krishna Kumari Challa on May 28, 2024 at 6:31am

Dyson spheres: Astronomers report potential candidates for alien structures, and evidence against their existence

There are three ways to look for evidence of alien technological civilizations. One is to look out for deliberate attempts by them to communicate their existence, for example, through radio broadcasts. Another is to look for evidence of them visiting the solar system. And a third option is to look for signs of large-scale engineering projects in space.

A team of astronomers have taken the third approach by searching through recent astronomical survey data to identify seven candidates for alien megastructures, known as Dyson spheres, "deserving of further analysis." Their research is published in the journal Monthly Notices of the Royal Astronomical Society.

This is a detailed study looking for "oddballs" among stars—objects that might be alien megastructures. However, the authors are careful not to make any overblown claims. The seven objects, all located within 1,000 light-years of Earth, are "M-dwarfs"—a class of stars that are smaller and less bright than the sun.
Dyson spheres were first proposed by the physicist Freeman Dyson in 1960 as a way for an advanced civilization to harness a star's power. Consisting of floating power collectors, factories and habitats, they'd take up more and more space until they eventually surrounded almost the entire star like a sphere.

What Dyson realized is that these megastructures would have an observable signature. Dyson's signature (which the team searched for in the recent study) is a significant excess of infrared radiation. That's because megastructures would absorb visible light given off by the star, but they wouldn't be able to harness it all. Instead, they'd have to "dump" excess energy as infrared light with a much longer wavelength.
Part 1

Comment by Dr. Krishna Kumari Challa on May 27, 2024 at 6:52am

Anendophasia: not having any inner speech

In recent years have scientists found that not everyone has the sense of an inner voice – and a new study sheds some light on how living without an internal monologue affects how language is processed in the brain.

This is similar to anauralia, a term researchers coined in 2021 for people who don't have an inner voice, nor can they imagine sounds, like a musical tune or siren.

Focusing on inner voices in a study, a research  team recruited 93 volunteers, half of whom said they had low levels of inner speech, while the other half reported having a very chatty internal monologue. These participants attempted a series of tasks – including one where they had to remember the order of words in a sequence, and another where rhyming words had to be paired together.

It is a task that will be difficult for everyone, but the  hypothesis of the researchers was that it might be even more difficult if people  did not have an inner voice because they have to repeat the words to themselves inside their head in order to remember them.

And this hypothesis turned out to be true.

The volunteers who reported hearing inner voices during everyday life did significantly better at the tasks than those without inner monologues: Inner speakers recalled more words correctly, and matched rhyming words faster. The researchers think this could be evidence that inner voices help people process words.

It's interesting to note that the performance differences disappeared when the volunteers spoke out loud to try and solve the problems they were given. It may be that using an audible voice is just as effective as using an inner voice in these situations.

In two other tasks, covering multitasking and distinguishing between different picture shapes, there was no difference in performance. The researchers take this as a sign that the way inner speech affects behavior depends on what we're doing.

Maybe people who don't have an inner voice have just learned to use other strategies. For example, some said that they tapped with their index finger when performing one type of task and with their middle finger when it was another type of task.

The researchers are keen to emphasize that the differences they found would not cause delays that you would notice in regular conversation. Scientists still at the very early stages in terms of figuring out how anendophasia might affect someone – and likewise anauralia.

https://journals.sagepub.com/doi/10.1177/09567976241243004

Comment by Dr. Krishna Kumari Challa on May 25, 2024 at 1:18pm

When a star more massive than about 8 times the mass of the Sun goes supernova, it's extremely messy. The outer layers – most of the star's mass – are explosively ejected into the space around the star, where they form a huge, expanding cloud of dust and gas that lingers for hundreds of thousands to millions of years.

Meanwhile, the star's core, no longer supported by the outward pressure of fusion, collapses under gravity to form an ultradense object, a neutron star or a black hole, depending on the initial star's mass.

These collapsed cores don't always stay put; if the supernova explosion is lopsided, this can punt the core off into space in a natal kick. We can also sometimes trace the core's trajectory back to the cloud of material it ejected as it died, but if enough time has elapsed, the material may have dissipated. But the signs of the natal kick can remain a lot longer.

VFTS 243 is a very interesting system. It consists of a massive star that's around 7.4 million years old and around 25 times the mass of the Sun, and a black hole around 10 times the mass of the Sun.

Although we can't see the black hole directly, we can measure it based on the orbital motion of its companion star – and, of course, we can infer other things about the system. One interesting thing is the shape of the orbit. It's almost circular. This, together with the motion of the system in space, suggests that the black hole did not receive a huge kick from a supernova. The researchers who discovered the black hole back in 2022 suspected as much; now, the work of Vigna-Gómez and his colleagues have confirmed it. There has been a growing body of evidence that suggests that sometimes, massive stars can collapse directly into black holes, without passing supernova or collecting 200 space dollars. VFTS 243 represents the best evidence we have for this scenario to date.

Our results highlight VFTS 243 as the best observable case so far for the theory of stellar black holes formed through total collapse, where the supernova explosion fails and which our models have shown to be possible," says astrophysicist Irene Tamborra of the Niels Bohr Institute. "It is an important reality check for these models. And we certainly expect that the system will serve as a crucial benchmark for future research into stellar evolution and collapse."

https://journals.aps.org/prl/abstract/10.1103/PhysRevLett.132.191403

Part 2

Comment by Dr. Krishna Kumari Challa on May 25, 2024 at 1:16pm

Why some huge stars have disappeared from the sky

When massive stars die, as we understand the Universe, they don't go quietly. As their fuel runs out, they become unstable, wracked by explosions before finally ending their lives in a spectacular supernova.

But some massive stars, scientists have found, have simply vanished, leaving no trace in the night sky. Stars clearly seen in older surveys are inexplicably absent from newer ones. A star isn't exactly a set of keys – you can't just lose it down the back of the couch. So where the heck do these stars go?

A new study has given us the most compelling explanation yet. Some massive stars, suggest an international team led by astrophysicist Alejandro Vigna-Gómez of the Niels Bohr Institute in Denmark and the Max Planck Institute for Astrophysics in Germany, can die, not with a bang, after all, but a whimper.

Their evidence? A binary system named VFTS 243 in the Large Magellanic Cloud, consisting of a black hole and a companion star. This system shows no signs of a supernova explosion that, according to the models, ought to have accompanied the formation of the black hole.

Were one to stand gazing up at a visible star going through a total collapse, it might, just at the right time, be like watching a star suddenly extinguish and disappear from the heavens.

The collapse is so complete that no explosion occurs, nothing escapes and one wouldn't see any bright supernova in the night sky. Astronomers have actually observed the sudden disappearance of brightly shining stars in recent times. Scientists cannot be sure of a connection, but the results they have obtained from analyzing VFTS 243 has brought them much closer to a credible explanation.

Part 1

Comment by Dr. Krishna Kumari Challa on May 25, 2024 at 11:44am

Big brands are 'failing to curb plastic sachet use'

Small plastic sachets commonly used in low- and middle-income countries must be phased out and packaging reuse systems promoted, urge campaigners and waste pickers, as new analysis reveals major corporations have failed to curb their use.

Pocket-sized individual portions of goods ranging from shampoo to instant coffee have become popular in lower-income communities for their affordability.

An estimated 855 billion sachets are sold globally each year with Southeast Asia consuming nearly half of the total and this figure projected to rise to 1.3 trillion by 2027, according to environmental groups.

But the convenience of sachets comes with a heavy environmental cost as they end up as significant contributors to plastic pollution. Their commonly multi-layered design, using different materials, makes them hard to recycle.

Consumer goods giants Unilever, Nestlé and Procter & Gamble are among the biggest contributors to plastic sachet pollution in developing countries in Asia, despite promises to reduce plastic packaging, according to a multi-country environmental audit report.

It said some corporations were trying to deal with the waste problem by burning sachets as fuel, creating further pollution.

Environmental groups in Asia have long been demanding firms to phase out their sachet packaging as the resulting waste is deluging the region's landfills and waters.

Consumers, can you please help by avoiding these small plastic sachet based products?

Source: SciDev.Net

Comment by Dr. Krishna Kumari Challa on May 25, 2024 at 9:02am

Many plants and plant oils are high in monounsaturated fats but low in saturated fats. These include: oils from olives, peanuts, canola seeds, safflower seeds, and sunflower seeds, avocadoes, pumpkin seeds, sesame seeds, almonds,  cashews, peanuts and peanut butter, pecans.

Air pollution is a complex issue with no easy solutions. While research continues mitigating PM2.5 exposure, the current understanding of its impact on the digestive system highlights the far-reaching consequences of air pollution on human health. It underscores the need for continued efforts to reduce air pollution levels and develop strategies to protect ourselves from its detrimental effects.

Kezhong Zhang, Environmental PM2.5-triggered stress responses in digestive diseases, eGastroenterology (2024). DOI: 10.1136/egastro-2024-100063

Part 2

Comment by Dr. Krishna Kumari Challa on May 25, 2024 at 9:00am

How air pollution affects the digestive system

Fine air particles, less than 2.5 micrometers in diameter (PM_2.5), are a major air pollutant linked to various health problems. These particles can travel deep into the lungs and even enter the bloodstream when inhaled. Recent research suggests a major health concern: PM_2.5 exposure can also damage the digestive system, including the liver, pancreas, and intestines.

The work is published in the journal eGastroenterology. This recent research has been focused on how PM2.5 exposure triggers stress responses within the digestive system's cells. These stress responses involve specialized subcellular structures within cells called organelles, such as the endoplasmic reticulum (ER), mitochondria, and lysosomes. When PM2.5 disrupts these organelles, it creates a chain reaction within the cells that can lead to inflammation and other harmful effects.

The liver, a major organ for detoxification and metabolism, is particularly susceptible to PM_2.5 damage. Studies have shown that PM_2.5 exposure can lead to a cascade of problems within the liver, including inflammation, stress responses, and damage to the organelles, and disrupted energy metabolism. These effects can contribute to the development of non-alcoholic fatty liver disease (NASH) and type 2 diabetes.

PM_2.5 exposure does not stop at the liver. It can also harm the pancreas and intestines. Studies have linked PM_2.5 to an increased risk of pancreatic impairment in people with diabetes, as well as damage to intestinal cells and an increase in their permeability. This increased permeability can lead to a variety of digestive issues.

Researchers are exploring whether dietary or pharmaceutical interventions can mitigate PM_2.5 damage. Interestingly, some studies suggest that certain nutrients, like monounsaturated fatty acids and vitamins, may offer some protection against the harmful effects of PM_2.5.

Part 1

Comment by Dr. Krishna Kumari Challa on May 25, 2024 at 7:09am

Replicated, long-term studies from natural populations, including research on the famous Darwin's finches, are rare.

Because most of this work is restricted to one or few populations, it is difficult to draw inferences on repeatability among multiple evolutionary independent populations.

Such studies are challenging to implement not only because they take concerted effort, but also because you can't rush time.

Patrik Nosil et al, Evolution repeats itself in replicate long-term studies in the wild, Science Advances (2024). DOI: 10.1126/sciadv.adl3149. www.science.org/doi/10.1126/sciadv.adl3149

Part 2

Comment by Dr. Krishna Kumari Challa on May 25, 2024 at 7:08am

Biologists observe recurring evolutionary changes, over time, in stick insects

A long-standing debate among evolutionary scientists goes something like this: Does evolution happen in a predictable pattern or does it depend on chance events and contingency? That is, if you could turn back the clock, as celebrated scientist Stephen Jay Gould (1941–2002) described in his famous metaphor, "Replaying the Tape of Life," would life on Earth evolve, once again, as something similar to what we know now, or would it look very, very different?

Now researchers  report evidence of repeatable evolution in populations of stick insects in the paper "Evolution repeats itself in replicate long-term studies in the wild," in Science Advances. 

The team examined three decades of data on the frequency of cryptic color-pattern morphs in the stick insect species Timema cristinae in ten naturally replicate populations in California. T. cristinae is polymorphic in regard to its body colour and pattern. Some insects are green, which allows the wingless, plant-feeding insect to blend in with California lilac (Ceanothus spinosus) shrubs. In contrast, green striped morphs disappear against chamise (Adenostoma fasciculatum) shrubs.

Hiding among the plants is one of T. christinae's key defenses as hungry birds, such as scrub jays, are insatiable predators of the stick insects.

Bird predation is a constant driver shaping the insects' organismal traits, including coloration and striped vs. non-striped.

Scientists observed predictable 'up-and-down' fluctuations in stripe frequency in all populations, representing repeatable evolutionary dynamics based on standing genetic variation.

A field experiment demonstrates these fluctuations involved negative frequency-dependent natural selection (NFDS), where cryptic colour patterns are more beneficial when rare rather than common. This is likely because birds develop a 'search image' for very abundant prey.

At short time scales, evolution involving existing variations can be quite predictable. You can count on certain drivers always being there, such as birds feeding on the insects.

But at longer time scales, evolutionary dynamics become less predictable.

The populations might experience a chance event, such as a severe drought or a flooding event, that disrupts the status quo and thus, the predictable outcomes.

On long time scales, a new mutation in the species could introduce a rare trait. That's about as close to truly random as you can get.

Rare things are easily lost by chance, so there's a strong probability a new mutation could disappear before it gains a stronghold. 

Indeed, another species of Timema stick insect that also feeds on chamise either never had or quickly lost the mutations making the cryptic stripe trait. Thus, the evolution of stripe is not a repeatable outcome of evolution at this long scale.

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