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Comment by Dr. Krishna Kumari Challa on November 17, 2023 at 7:36am

Kelsey's ultrasound shows both of her uteruses with a baby in each. Source: (doubleuhatchlings/Instagram)

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Comment by Dr. Krishna Kumari Challa on November 16, 2023 at 11:41am

1 in 50 Million Chance: US Woman With Rare Double Uterus Is Pregnant in Both

 A 32-year-old woman from Alabama who was born with two uteruses is now pregnant in both.

Kelsey Hatcher, who is documenting her story on her Instagram account "doubleuhatchlings," knew from the age of 17 she has "uterus didelphys," a rare condition where a person has a double uterus, thought to affect about 0.3 percent of females.

It was during a routine eight-week ultrasound visit in May that the mother-of-three learned not only that she was having twins this time around – but that a fetus was present in each of her uteruses.

Most likely what happened is that she ovulated separately and had one egg come down each fallopian tube, meaning coming down on each side of the uterus, and then sperm traveled up on each separate uterus and fertilization occurred separately, according to her doctors. Both the fetuses are healthy.

Pregnancies in both uteruses are exceedingly rare – the odds were 1 in 50 million – with the last widely known case occurring in Bangladesh in 2019 when Arifa Sultana, then 20, gave birth to healthy twins 26 days apart.​

But the uteruses will contract at different times, which could be minutes, hours or even days apart, and the woman and her husband  are aware Cesarean sections – for one, or both – could be needed, depending on how things unfold.

Source: 

Agence France-Presse

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Comment by Dr. Krishna Kumari Challa on November 16, 2023 at 11:34am

50 Years of Data Links Insecticides to Global Decline of Human Sperm Counts: Meta Analysis

Insecticide exposure has been linked to lower sperm concentration in adult men worldwide, according to a new review of 25 studies spanning almost 50 years. The research team  says it's the most thorough systematic review of the topic so far.

These are strong findings as their method takes into account each study's limitations, so their published paper recommends reducing exposure to the two types of insecticides studied to preserve male fertility and increase the changes of parenthood.

people are primarily exposed to insecticides through the consumption of contaminated food and water.

These commonly-used insecticides' main mode of toxicity is the inhibition of enzymes involved in the normal breakdown of neurotransmitters like acetylcholine.

"No matter how you looked at it, the smaller studies or the larger studies, there was a consistent association with increased exposure to insecticides associated with decreased sperm concentration", according to the researchers.

The researchers note other studies have shown that semen quality is declining over time. A review in 2022 found that the average sperm count among participants, who were not considered infertile dropped by 51 percent between 1973 and 2018, from 101.2 million to 49 million per millilitre of semen.

There's a correlation between low sperm concentration and other factors of male health too, such as an increased risk of some cancers. However, finding two things to be related doesn't prove that one is responsible for or a result of the other, and we still don't know the mechanism behind the effects.

https://ehp.niehs.nih.gov/doi/10.1289/EHP12678

Comment by Dr. Krishna Kumari Challa on November 16, 2023 at 9:56am

Researchers discover alternative cosmic source of gold

Researchers have discovered that the explosion of a low-mass neutron star can be the alternative cosmic source for lanthanides and other heavy elements, including precious metals such as gold and platinum.

Neutron stars are the evolutionary end points of stars with a mass between 10 to 25 times that of the sun. After the final explosion, the star leaves behind a compact object with a mass comparable to the sun, and a diameter of about 20 km (the size of Manhattan). Such a compact object is stable enough to exist alone. But in a binary neutron star system, the interaction with the companion neutron star can trigger something dramatic. Traditionally, when two neutron stars are close enough, they merge and collide. This process is the major source of lanthanides and heavy elements in the universe. The collision can create the condition (known as the r-process) for the synthesis of these elements. The merger event was recently observed for the first time in 2017. However, it is highly uncertain if this channel alone is sufficient to explain the heavy elements in the cosmic scale. The team noticed that even without direct collision, the primary neutron star can lose mass to its companion neutron star by tidal force. Theoretical models expect that after shedding sufficient mass, the star becomes unstable, and it triggers uncontrolled pulsation and the later explosion.

The new results  confirm that the individual low mass neutron star is unstable, and it can explode. The chemical composition of the ejecta closely resembles the solar composition, especially in heavy elements. This suggests that this scenario could be another important method to explain the chemical element distribution in the universe.

This study sheds light on one of the fundamental questions about the universe: where all the chemical elements come from, and how did the universe evolve from only hydrogen and helium to a diversity of 118 elements. Lanthanides have close relations with modern technology. For example, neodymium is the main ingredient for manufacturing strong magnets. Heavy elements including precious metals, i.e., gold and platinum, are also abundantly produced by this channel.

 Chun-Ming Yip et al, R-process Nucleosynthesis of Subminimal Neutron Star Explosions, The Astrophysical Journal (2023). DOI: 10.3847/1538-4357/acf570

Comment by Dr. Krishna Kumari Challa on November 16, 2023 at 9:49am

Research models suggested that airflow from highly populated inland areas, rather than from over the ocean or other nearby mountains, served as the major source of the fragments.

In laboratory experiments, the researchers demonstrated that microplastics exposed to cloud-like conditions—ultraviolet light and filtered cloud-sourced water—had smaller sizes and rougher surfaces than those exposed to pure water or air. Additionally, particles impacted by the cloud-like conditions had more lead, mercury and oxygen-containing groups.

These results suggest that clouds modify microplastics in ways that could enable the particles to affect cloud formation and the fate of airborne metals. However, more work is needed to fully understand how microplastics affect clouds and the weather.

Characterization of Microplastics in Clouds over Eastern China, Environmental Science & Technology Letters (2023). DOI: 10.1021/acs.estlett.3c00729. pubs.acs.org/doi/abs/10.1021/acs.estlett.3c00729

Part 2

Comment by Dr. Krishna Kumari Challa on November 16, 2023 at 9:47am

Microplastics found in clouds could affect the weather

From the depths of the seas to snow on mountains and even the air above cities, microplastics are turning up increasingly often. Now, in Environmental Science & Technology Letters, researchers have analyzed microplastics in clouds above mountains. They suggest that these tiny particles could play a role in cloud formation and, in turn, affect weather.

Microplastics—plastic fragments smaller than five millimeters—originate from a myriad of items used daily, such as clothing, packaging and car tires.

As research in the field evolves, scientists are not only detecting microplastics in the atmosphere but also investigating how they may play a role in cloud formation. For example, a group of researchers recently detected plastic granules, which had water-attracting surfaces, in Japanese mountaintop clouds.

So, to learn more, researchers set out to look for microplastics in mountain clouds, used computer models to figure out how they could have gotten there, and tested how the particles could have impacted—and been impacted by—the clouds.

Wang and the team first collected 28 samples of liquid from clouds at the top of Mount Tai in eastern China. Then they analyzed the samples and found:

• Low-altitude and denser clouds contained greater amounts of microplastics.
• Particles were made of common polymers, including polyethylene terephthalate, polypropylene, polyethylene, polystyrene and polyamide.
• The microplastics tended to be smaller than 100 micrometers in length, although some were as long as 1,500 micrometers.
• Older, rougher particles had more lead, mercury and oxygen attached to their surfaces, which the researchers suggest could facilitate cloud development.

Part 1

Comment by Dr. Krishna Kumari Challa on November 16, 2023 at 9:37am

Data reveal possible reason some exoplanets are shrinking

A new study could explain the "missing" exoplanets between super-Earths and sub-Neptunes.

Some exoplanets seem to be losing their atmospheres and shrinking. In a new study using NASA's retired Kepler Space Telescope, astronomers find evidence of a possible cause: The cores of these planets are pushing away their atmospheres from the inside out.

The study is published in The Astronomical Journal.

Exoplanets (planets outside our solar system) come in a variety of sizes, from small, rocky planets to colossal gas giants. In the middle lie rocky super-Earths and larger sub-Neptunes with puffy atmospheres. But there's a conspicuous absence—a "size gap"—of planets that fall between 1.5 to 2 times the size of Earth (or in between super-Earths and sub-Neptunes) that scientists have been working to better understand.

Scientists have now confirmed the detection of over 5,000 exoplanets, but there are fewer planets than expected with a diameter between 1.5 and 2 times that of Earth. Exoplanet scientists have enough data now to say that this gap is not a fluke. There's something going on that impedes planets from reaching and/or staying at this size.

Researchers think that this gap could be explained by certain sub-Neptunes losing their atmospheres over time. This loss would happen if the planet doesn't have enough mass, and therefore gravitational force, to hold onto its atmosphere. So sub-Neptunes that aren't massive enough would shrink to about the size of super-Earths, leaving the gap between the two sizes of planets.

But exactly how these planets are losing their atmospheres has remained a mystery. Scientists have settled on two likely mechanisms: One is called core-powered mass loss; and the other, photoevaporation. The new study has uncovered new evidence supporting the first.

 Jessie L. Christiansen et al, Scaling K2. VII. Evidence For a High Occurrence Rate of Hot Sub-Neptunes at Intermediate Ages, The Astronomical Journal (2023). DOI: 10.3847/1538-3881/acf9f9

Comment by Dr. Krishna Kumari Challa on November 16, 2023 at 9:34am

Exoplanet Types: Worlds Beyond Our Solar System

Comment by Dr. Krishna Kumari Challa on November 15, 2023 at 9:15am

Our Galaxy's Heart Is Pulsing With a Mysterious Signal

Compared to some other galaxies out there, the supermassive black hole at the heart of the Milky Way isn't a particularly active one. It's not guzzling down scads of material, and it's not blasting giant jets of plasma into space. Even a relatively peaceful supermassive black hole, however, is a wild, savage beast, and our own – named Sagittarius A* – has been recorded doing some pretty strange things. And now there's a new one: astrophysicists Gustavo Magallanes-Guijón and Sergio Mendoza of National Autonomous University of Mexico have recorded it sort of… pulsing. Every 76 minutes, like clockwork, the gamma-ray flux of Sgr A fluctuates. This, the researchers say, is similar in periodicity to changes in the black hole's radio and X-ray emission too, suggesting an orbital motion of something whirling madly around the black hole.

https://arxiv.org/abs/2311.05875

Comment by Dr. Krishna Kumari Challa on November 15, 2023 at 9:08am

All fireworks, including the green ones, are bad ! Did you know that Deepavali fireworks cause more distress than happiness? So we celebrate Diwali without any fireworks! All these years I never ever touched even a single one. We have been celebrating  Deepavali with fun and happiness minus fireworks for the past few years. Before somebody asks me 'How can there be fun without fireworks?', I want to add I had fun because I didn't contribute to the pollution. I didn't send out a toxic concoction into the atmosphere that rains down heavily into lakes, rivers, seas, fields and houses. I am not responsible for someone developing hypothyroidism, anemia or cancer. And I am extremely happy because of this! Fireworks get their flamboyance from a variety of chemicals, many of which are toxic to humans. From the gunpowder that fuels their flight to the metallic compounds that colour their explosions, fireworks often contain carcinogenic or hormone-disrupting substances that can seep into soil and water, not to mention the lung-clogging smoke they release and plastic debris they scatter. Almost all the major cities in India that have measured Deepavali festival-raised pollution levels recently sounded alarm bells. Some people justify their acts of using fireworks by saying that these harmful gases released into the atmosphere actually kill mosquitoes and other harmful insects! But these insects might already have developed resistance to these chemicals. Moreover, if they are harmful to some living beings, they would equally be harmful to the other ones (human beings) too! First the ever evolving fireworks tempt you and make you buy them at sky-rocketing prices causing distress to your earning loved ones. Fire accidents are quite common during this festival. The flying fire bits also get into unprotected eyes and burn eye parts, especially the cornea leading to blindness. Apart from causing agony to the animal life, the loud noises also increase hearing distress and the toxic smoke released into the atmosphere can get lodged in people's lungs and enhance asthmatic symptoms and severe breathing problems in human beings. Anybody considering him/her-self environmentally conscious and responsible will never go anywhere near these fireworks as they pose a serious environmental and health danger from heavy metals and other toxic firework fallout. So celebrate Diwali without fireworks like we do. 

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