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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

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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

Comment by Dr. Krishna Kumari Challa on October 19, 2023 at 6:55am

Previous attempts have tried to make super lenses using novel materials. However, most materials absorb too much light to make the super lens useful.

Now researchers overcame this by performing the superlens operation as a post-processing step on a computer, after the measurement itself. This produces a 'truthful' image of the object through the selective amplification of evanescent (or vanishing) light waves.

This method could be applied to determine moisture content in leaves with greater resolution, or be useful in advanced microfabrication techniques, such as non-destructive assessment of microchip integrity. And the method could even be used to reveal hidden layers in artwork, perhaps proving useful in uncovering art forgery or hidden works.

 Subwavelength terahertz imaging via virtual superlensing in the radiating near field, Nature Communications (2023). DOI: 10.1038/s41467-023-41949-5

Part 2

Comment by Dr. Krishna Kumari Challa on October 19, 2023 at 6:54am

Superlensing without a super lens: Physicists boost microscopes beyond limits

Ever since Antonie van Leeuwenhoek discovered the world of bacteria through a microscope in the late seventeenth century, humans have tried to look deeper into the world of the infinitesimally small.

There are, however, physical limits to how closely we can examine an object using traditional optical methods. This is known as the diffraction limit and is determined by the fact that light manifests as a wave. It means a focused image can never be smaller than half the wavelength of light used to observe an object.

Attempts to break this limit with "super lenses" have all hit the hurdles of extreme visual losses, making the lenses opaque. Now physicists  have shown a new pathway to achieve superlensing with minimal losses, breaking through the diffraction limit by a factor of nearly four times. The key to their success was to remove the super lens altogether.

The work should allow scientists to further improve super-resolution microscopy, the researchers say. It could advance imaging in fields as varied as cancer diagnostics, medical imaging, or archaeology and forensics.

Researchers have now developed a practical way to implement superlensing, without a super lens. To do this, they placed their light probe far away from the object and collected both high- and low-resolution information. By measuring further away, the probe doesn't interfere with the high-resolution data, a feature of previous methods.

Part 1

Comment by Dr. Krishna Kumari Challa on October 18, 2023 at 9:50am

Digitally creating 16 million colours by chemistry

The DNA double helix is composed of two DNA molecules whose sequences are complementary to each other. The stability of the duplex can be fine-tuned in the lab by controlling the amount and location of imperfect complementary sequences.

Fluorescent markers bound to one of the matching DNA strands make the duplex visible, and fluorescence intensity increases with increasing duplex stability. Now, researchers  succeeded in creating fluorescent duplexes that can generate any of 16 million colours—a work that surpasses the previous 256 colours limitation.

This very large palette can be used to "paint" with DNA and to accurately reproduce any digital image on a miniature 2D surface with 24-bit color depth.

Tadija Kekić et al, A Canvas of Spatially Arranged DNA Strands that Can Produce 24-bit Color Depth, Journal of the American Chemical Society (2023). DOI: 10.1021/jacs.3c06500

Comment by Dr. Krishna Kumari Challa on October 17, 2023 at 10:47am

The researchers found that the secondary magnet (which they call a floater) rotated in sync with the rotor magnet—they spun at the same speed. They also found that the axis of the rotor magnet spun with a slight tilt—a situation that would destabilize the two magnets if they were not spinning. To better understand what was happening, the researchers created a simulation that allowed them to more easily manipulate the two magnets and their behavior.

They found that the magnetic field of the rotor magnet exerted some amount of torque on the floater resulting in the two magnets rotating in sync due to a gyroscopic effect. But the floater resisted, if only slightly, which accounted for the parallel configuration that developed. They also found that there was a very small amount of misalignment of the polar axis of the rotor magnet relative to its magnetic field—the resulting attractive and repulsive forces balanced each other out, allowing the floater to be held in a steady position during levitation.

Joachim Marco Hermansen et al, Magnetic levitation by rotation, Physical Review Applied (2023). DOI: 10.1103/PhysRevApplied.20.044036. On arXiv: doi.org/10.48550/arXiv.2305.00812

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