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Comment by Dr. Krishna Kumari Challa on October 21, 2023 at 9:33am

10 billion snow crabs starved to death in the Bering Sea because ...

A team of marine biologists has solved the mystery of why approximately 10 billion snow crabs vanished from the Bering Sea back in 2018/2019—the water there was too warm for them!

In their study, reported in the journal Science, the group used data from previous studies on the way snow crabs respond to warmer temperatures to solve the mystery.

Snow crabs are relatively small crabs, that, despite their name, are not white—they are red, like lobsters. They live on the ocean floor in shallow areas and have been consumed as a seafood delicacy for many years.

Alaskan fishermen (and scientists) first noticed a dramatic decline in their numbers back in 2021. Then, due to the pandemic, fishing and studying of the crabs was put on hiatus for a year. The full extent of the crab disappearance was only observed earlier in 2023—over 10 billion were missing. Upon discovering this alarming decline, a research team set to work to figure out what happened.

The team started by scouting nearby areas, hoping that the crabs had simply moved to another location, but no sign of them could be found. Next, noting that the area had experienced a heat wave prior to, and during, the crab disappearance they turned to the results of a prior study that had found that when water temperatures increase, energy requirements for the crabs increase. The researchers found that if water temperatures increased by just 3°C, the caloric needs of the crabs doubled.

Records showed that during the heat wave, water temperatures had risen 3°C, which meant the crabs would have needed twice as much food to sustain themselves. The research team also found that just prior to the heat wave, the crab population had risen dramatically, meaning that there had been a large increase in competition for food. And that, the researchers conclude, led the crabs to starve to death.

Need we give more evidence to  what might happen to the heat sensitive creatures during  global warming?

Cody S. Szuwalski et al, The collapse of eastern Bering Sea snow crab, Science (2023). DOI: 10.1126/science.adf6035

Gordon H. Kruse, Are crabs in hot water?, Science (2023). DOI: 10.1126/science.adk7565

Comment by Dr. Krishna Kumari Challa on October 21, 2023 at 9:16am

Evidence of Earth's core leaking found 

A  team of geochemists has found evidence of high levels of helium-3 in rocks on Baffin Island—possible evidence that the Earth's core is leaking. 

Prior researchers found trace elements of helium-3 in lava flows on Baffin Island, hinting at the possibility that the Earth's core might be leaking. This is because it is an ancient isotope—it was prevalent during the time when Earth was forming and became trapped in the core. But because of its nature, helium-3 that makes its way to the surface soon escapes into the atmosphere and disappears into space. Thus, helium-3 is rare. If it is found on the surface, the odds are high that it made its way out of the core.

Intrigued by the possibility that the Earth's core might be leaking, the research team ventured to Baffin Island and began testing multiple lava flows. They found much higher levels of helium-3 than observed in prior research efforts—higher than anywhere else on Earth. They also found high ratios of helium-3 to helium-4 (a common isotope)—the highest that have ever been measured in terrestrial rock. Such high ratios, the researchers suggest, is another factor suggesting that the helium-3 is leaking from the core.

The research team notes that finding such high levels of helium-3 at a terrestrial site is a big deal, because if it can be proved that the material is indeed leaking from the core, it will provide scientists with a way to study core material, which has never been done before. That could reveal more about the core than previously thought possible. They note that if the helium-3 is coming from the core, then the other material around it should be as well, offering further physical examples of core material.

F. Horton et al, Highest terrestrial 3He/4He credibly from the core, Nature (2023). DOI: 10.1038/s41586-023-06590-8

Comment by Dr. Krishna Kumari Challa on October 20, 2023 at 11:37am

In particular, just before ovulation, when the hormones 17β-estradiol and luteinizing hormone rise, the brains of the participants showed white matter changes suggesting faster information transfer.

Follicle-stimulating hormone, which rises before ovulation, and helps stimulate the ovary follicles, was associated with thicker gray matter.

Progesterone, which rises after ovulation, was associated with increased tissue and decreased cerebrospinal fluid volume.

What this means for the person driving the brain is unknown, but the research lays the groundwork for future studies, and perhaps understanding the causes of unusual but severe period-related mental health problems.

These findings may have implications for hormone-driven alterations in behavior and cognition," the researchers write.

https://www.biorxiv.org/content/10.1101/2023.10.09.561616v1

Part 2

Comment by Dr. Krishna Kumari Challa on October 20, 2023 at 11:36am

Scientists Show Structural, Brain-Wide Changes During Menstruation

The constant ebb and flow of hormones that guide the menstrual cycle don't just affect reproductive anatomy. They also reshape the brain, and a new study has given us insight into how this happens.

A team of researchers tracked 30 women who menstruate over their cycles, documenting in detail the structural changes that take place in the brain as hormonal profiles fluctuate.

The results, which are yet to be peer-reviewed but can be found on preprint server bioRxiv, suggest that structural changes in the brain during menstruation may not be limited to those regions associated with the menstrual cycle.

These results are the first to report simultaneous brain-wide changes in human white matter microstructure and cortical thickness coinciding with menstrual cycle-driven hormone rhythms," the researchers write.

Strong brain-hormone interaction effects may not be limited to classically known hypothalamic-pituitary-gonadal-axis (HPG-axis) receptor-dense regions.

Cyclic fluctuations in HPG-axis hormones exert powerful behavioural, structural, and functional effects through actions on the mammalian central nervous system.

The microstructure of white matter – the fatty network of neuronal fibers that transfer information between regions of gray matter – has been found to change with hormonal shifts, including puberty, oral contraception use, gender-affirming hormone therapy, and post-menopausal estrogen therapy.

To address the menstruation gap in our understanding, the team took MRI scans of their subjects during three menstrual phases: menses, ovulation, and mid-luteal. At the time of each of these scans, the researchers also measured the participants' hormone levels.

The results showed that, as hormones fluctuate, gray and white matter volumes change too, as does the volume of cerebrospinal fluid.

Part 1

Comment by Dr. Krishna Kumari Challa on October 20, 2023 at 9:46am

Gray whales make the longest migration of any mammal on Earth, traveling more than 12,000 miles every year from their foraging grounds in the Arctic, where they spend the summers, to their breeding grounds in the warm, shallow lagoons of Mexico's Baja Peninsula, where they spend the winters.

While in the Arctic, the gray whales feed on amphipod crustaceans. Amphipods in turn feed on algae, which grows on the underside of sea ice.

With less ice, you get less algae, which is worse for the gray whale prey. When there are sudden declines in the quality of prey, the population of gray whales is significantly affected.

In other words, the melting sea ice disrupts the entire food chain.

The decrease in available food can cause skinnier or malnourished whales, as well as lower birth rates.

Even highly mobile, long-lived species such as gray whales are sensitive to climate change impacts.

Part 2

**

https://www.businessinsider.in/science/news/gray-whales-have-been-m...

Comment by Dr. Krishna Kumari Challa on October 20, 2023 at 9:43am

Mystery of Dead Whales Washing Up on US Coast May Be Solved

Gray whales have been washing up dead on the Pacific coast at an alarming rate since 2019, and scientists think they might finally know why.

The gray whale strandings from Mexico all the way to Alaska have been declared an "unusual mortality event," or a significant die-off of a species that is unexplained and requires a quick response.

Two other mass die-offs of gray whales occurred in the 1980s and 1990s, though those only lasted a couple of years; the latest is still ongoing. The latest die-off has caused the North Pacific gray whale population to plummet from an estimated 27,000 in 2016 to 14,500 in 2023, according to the National Oceanic and Atmospheric Administration. For years, researchers could only guess what was killing the whales. NOAA has previously noted that emaciation had been observed in some of the dead whales, but not in others. But scientists at Oregon State University's Marine Mammal Institute now say there is strong evidence that the whale deaths are linked directly to sea ice melting in the Arctic, according to a study published recently in the journal Science.

The decrease in sea ice was also causing the gray whales' food supply to diminish.

Part 1

Comment by Dr. Krishna Kumari Challa on October 20, 2023 at 9:31am

Robots helped understand how insects evolved two distinct strategies of flight

Comment by Dr. Krishna Kumari Challa on October 20, 2023 at 9:15am

Scientists develop innovative magnetic gel that heals diabetic wounds three times faster

Diabetic patients whose natural wound-healing capabilities are compromised often develop chronic wounds that are slow to heal. Such non-healing wounds could cause serious infections resulting in painful outcomes, such as limb amputation. To address this global health care challenge, a team of researchers  engineered an innovative magnetic gel that promises to accelerate the healing of diabetic wounds, reduce the rates of recurrence, and in turn, lower the incidents of limb amputations.

Each treatment involves the application of a bandage pre-loaded with a hydrogel containing skin cells for healing and magnetic particles. To maximize therapeutic results, a wireless external magnetic device is used to activate skin cells and accelerate the wound healing process. The ideal duration of magnetic stimulation is about one to two hours.

Lab tests showed the treatment coupled with magnetic stimulation healed diabetic wounds about three times faster than current conventional approaches. Furthermore, while the research has focused on healing diabetic foot ulcers, the technology has potential for treating a wide range of complex wounds such as burns.

Yufeng Shou et al, Mechano‐activated Cell Therapy for Accelerated Diabetic Wound Healing, Advanced Materials (2023). DOI: 10.1002/adma.202304638

Comment by Dr. Krishna Kumari Challa on October 19, 2023 at 7:09am

Simulating cold sensation without actual cooling

Our skin plays a key role in perceiving temperature and the surroundings. For instance, we perceive the chill of the outdoors when our cheeks blush with cold, and we sense the onset of spring when our skin warms up gradually.

However, getting exposed to the same stimuli repeatedly, makes us accustomed to the stimuli, making it challenging to sense new sensations. This process, known as "temperature acclimatization," can interfere with our ability to gauge temperature changes in a virtual reality (VR) environment while switching scenes.

In a new study, researchers have developed a non-contact technology for simulating a cold sensation that continually generates thermal experiences while maintaining nearly constant skin temperature. This innovative approach leverages human body's natural sensitivity to rapid temperature changes.

The technology employs a combination of cold air flow and a light source to instantly switch between a quick cold and a gentle warm stimulus, inducing a cold sensation while maintaining the skin temperature fluctuations close to zero. Evaluation results have demonstrated that this system can provide a virtual cold sensation without any actual change in temperature. Moreover, the researchers have succeeded in replicating a cold sensation of the same intensity as one would experience with continuous skin temperature changes.

This technology offers a novel perspective on simulating skin sensations without altering the body's physical state. 

Jiayi Xu et al, Integration of Independent Heat Transfer Mechanisms for Non-Contact Cold Sensation Presentation With Low Residual Heat, IEEE Transactions on Haptics (2023). DOI: 10.1109/TOH.2023.3324754

Comment by Dr. Krishna Kumari Challa on October 19, 2023 at 7:05am

Researchers discover one of the world's darkest rivers

When the researchers came upon the Ruki River, they were quite taken aback. The water in this river, a tributary of the mighty Congo River, is so dark that you literally can't see your hand in front of your face.

Comparisons with other major tropical rivers show that the Ruki may even be the blackest large blackwater river on Earth—it's certainly a lot darker than the famous Rio Negro in the Amazon. The reason the water is black is that it contains large amounts of dissolved organic material and hardly any sediment because of the river's low gradient. These carbon-rich substances are mostly washed into the river by the rain, which falls on dead jungle vegetation and leaches out organic compounds from the decomposing plant material. What's more, the river floods the forest in the rainy season. It can take weeks for the often waist-deep water to slowly retreat, during which time it leaches organic substances.

The Ruki is one of the most DOC-rich river systems in the world (dissolved organic carbon). DOC usually comes in the form of organic acids that increase the acidity of the river water. This stimulates the release of carbon dioxide (CO₂) as the acids dissolve carbonates present in the water.

Travis W. Drake et al, Hydrology drives export and composition of carbon in a pristine tropical river, Limnology and Oceanography (2023). DOI: 10.1002/lno.12436

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