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Comment by Dr. Krishna Kumari Challa on Sunday

Why your faucet drips: Water jet breakup traced to angstrom-scale thermal capillary waves

The breakup of a water jet into droplets is primarily triggered by intrinsic thermal capillary waves—angstrom-scale surface fluctuations—rather than external disturbances or nozzle imperfections. These minute thermal oscillations are amplified by Rayleigh-Plateau instability, determining the breakup length across a wide range of jet sizes.

Stefan Kooij et al, What Determines the Breakup Length of a Jet?, Physical Review Letters (2025). DOI: 10.1103/jf6w-l5sy

Comment by Dr. Krishna Kumari Challa on Sunday

Fatty food smells during pregnancy may raise obesity risk in offspring

Exposure to fatty food odors during pregnancy and breastfeeding, even without maternal weight gain or high-fat intake, can alter offspring brain circuits related to reward and metabolism, increasing their risk of obesity and insulin resistance. Ingested flavoring agents with fatty odors were sufficient to trigger these effects in mice, highlighting potential implications for human metabolic health.

https://medicalxpress.com/news/2025-12-fatty-food-pregnancy-obesity...

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Comment by Dr. Krishna Kumari Challa on Sunday

Why dogs hide food and toys

No, they  aren't stockpiling their food due to anxiety about impending disaster. 

Instead, they're revealing how their evolutionary past still shapes modern behaviors. This forward-thinking strategy offers us a unique window into how we can help them live well. 

"Caching," is the scientific term for storing food in hidden places for later use. This behaviour is widespread across the animal kingdom, from squirrels, to crows, and wolves.

Caching behavior generally falls into one of two categories.

One is known as larder hoarding—think of a squirrel stashing nuts in just one or two places to draw from as they get through a long winter. 

 The other is known as scatter hoarding. It is where animals make smaller caches of surplus food in many different locations, reducing the chance of losing everything to a competitor or going hungry in lean seasons. It's mostly seen in wild canids such as foxes and wolves.  

This behavior in modern dogs is an instinctual remnant. It reflects the competitive feeding patterns of their ancestors who lived by hunting, for whom securing food was unpredictable, but crucial for survival. 

 Dogs appear to rely on a combination of scent and observational spatial memory to remember where they have cached special items, such as food, treats and toys.

https://theconversation.com/your-dog-is-not-a-doomsday-prepper-here...

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Comment by Dr. Krishna Kumari Challa on Sunday

Images that require less neural energy to process are generally rated as more aesthetically pleasing, indicating that visual preference may be influenced by the brain's tendency to conserve energy. This suggests that aesthetic appreciation is linked to a balance between adequate visual stimulation and minimizing metabolic expenditure.

 

Beauty may be 'easy on the eyes' because it saves brain power

Humans may find images that take less energy to process aesthetically pleasing, suggesting that our attraction to beauty is at least partially an energy conservation strategy. 

Looking at something can feel effortless, but in energetic terms, it isn't cheap. The brain uses 20% of the body's energy, and the visual system accounts for about 44% of that expenditure. Looking at very simple stimuli, like a blank white room, is energy-efficient but boring. Looking at very busy or unusual images can feel tiring and unpleasant. 

Publishing in PNAS Nexus, researchers presented 4,914 images of objects and scenes to an in-silico model of the visual system to estimate the number of neurons needed to look at them. The authors compared these estimates to enjoyment ratings from 1,118 participants recruited using Amazon Mechanical Turk.

Next, they used blood oxygen level-dependent signal brain imaging to measure the energy costs of looking at images for 4 participants. In both experiments, study participants found images that took less energy to process more attractive. The authors asked for a quick response, meant to capture initial impressions, not the more complex pleasures that may arise from contemplating an image in a broader context by engaging with its meaning.

According to the authors, visual aesthetic appreciation may be a manifestation of an energy-conserving heuristic that creates a sweet spot between sufficient stimulation of the visual system and excessive metabolic cost.

Yikai Tang et al, Less is more: Aesthetic liking is inversely related to metabolic expense by the visual system, PNAS Nexus (2025). DOI: 10.1093/pnasnexus/pgaf347

Comment by Dr. Krishna Kumari Challa on Sunday

Cancer-promoting DNA circles hitchhike on chromosomes to spread to daughter cells

Extrachromosomal DNA circles (ecDNA) in cancer cells persist by attaching to chromosomes during cell division using specific retention elements, mimicking natural gene regulation mechanisms. Disrupting this attachment, such as by adding methyl groups to retention elements, leads to ecDNA loss and reduced cancer cell survival, highlighting a potential therapeutic target for cancer treatment.

Venkat Sankar et al, Genetic elements promote retention of extrachromosomal DNA in cancer cells, Nature (2025). DOI: 10.1038/s41586-025-09764-8

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Comment by Dr. Krishna Kumari Challa on Sunday

Playing specific bat-like ultrasounds can suppress moth reproduction, offering a smart way to protect crops Exposure to bat-like ultrasonic pulses alters the behavior of Autographa nigrisigna moths, with higher pulse repetition rates causing erratic flight or flight cessation, especially in egg-bearing females. This response reduces egg-laying and suggests that ultrasonic cues can be used to suppress moth reproduction, offering a potential environmentally friendly method for crop protection.

Ming Siang Lem et al, Ultrasonic pulse repetition rates triggering escape responses of a moth pest, Pest Management Science (2025). DOI: 10.1002/ps.70204

Comment by Dr. Krishna Kumari Challa on Sunday

Scientists call for greater focus on conserving whole ecosystems instead of charismatic species

Conservation programs are often too focused on a single charismatic species.

 

With many species worldwide experiencing population declines, there is an urgent need for conservation initiatives to support their recovery. However, this urgency, combined with insufficient scientific knowledge about endangered species, means that conservationists have often relied on oversimplified measures of success. For example, historical conservation efforts often focused on the abundance of a single charismatic species as a proxy for overall ecosystem health.

 

Researchers highlight three examples from China where oversimplified conservation priorities led to negative outcomes. The Chinese giant salamander (Andrias davidianus) is known as a "cryptic species," because it has multiple, genetically distinct populations that look identical to the naked eye.

Unaware of this, conservationists began a large-scale captive breeding and reintroduction program, which led to genetic mixing that threatened native populations. In the case of the crested Ibis (Nipponia nippon) and Père David's deer (Elaphurus davidianus), intensive captive breeding and release programs with limited suitable habitat have resulted in overcrowding, inbreeding and increased mortality.

Although well-intentioned, these initiatives have caused unforeseen issues for the ecosystem, and have often failed to improve the conservation status of the target species.

To avoid repeating these mistakes, the researchers advocate for a more nuanced approach to conservation, focused on creating balanced ecosystems, restoring habitats and minimizing human intervention. Although there has recently been more emphasis placed on protecting whole ecosystems, charismatic species conservation is still prevalent in the world.

Conservation programs that aim to preserve and restore ecosystem functions are a more effective use of limited resources, and are less likely to have unintended consequences, the researchers say. 

Shi H-T, et al. Are we over-conserving charismatic species? PLOS Biology (2025). DOI: 10.1371/journal.pbio.3003494

Comment by Dr. Krishna Kumari Challa on Sunday

Cancer cells keep their chromosomes intact to continue dividing relentlessly

Cancer cells maintain their ability to divide by using telomerase to repair chromosome ends (telomeres). An internal actin protein network in the nucleus helps telomerase access damaged telomeres, supporting cell survival even after chemotherapy-induced DNA damage. Targeting telomerase or this actin network could enhance chemotherapy effectiveness and reduce side effects.

Ashley Harman et al, Nuclear actin and DNA replication stress regulate telomere maintenance by telomerase, Nature Communications (2025). DOI: 10.1038/s41467-025-66506-0

Comment by Dr. Krishna Kumari Challa on Sunday

Fossils reveal anacondas have been giants for over 12 million years

Researchers  analyzed giant anaconda fossils from South America to deduce that these tropical snakes reached their maximum size 12.4 million years ago and have remained giants ever since.

Many animal species that lived 12.4 to 5.3 million years ago, in the period known as the "Middle to Upper Miocene," were much bigger than their modern relatives due to warmer global temperatures, extensive wetlands and an abundance of food.

While other Miocene giants—like the 12-meter caiman (Purussaurus) and the 3.2-meter giant freshwater turtle (Stupendemys)—have since gone extinct, anacondas (Eunectes) bucked the trend by surviving as a giant species.

Anacondas are among the largest living snakes in the world. They are usually four to five meters long and in rare cases can reach seven meters.

The team measured 183 fossilized anaconda backbones, representing at least 32 snakes, discovered in Falcón State in Venezuela, South America. Combining these measurements with fossil data from other sites in South America allowed them to calculate that ancient anacondas would have been four to five meters long. This matches the size of anacondas that exist today. 

An early origin of gigantism in anacondas (Serpentes: Eunectes) revealed by the fossil record, Journal of Vertebrate Paleontology (2025). DOI: 10.1080/02724634.2025.2572967

Comment by Dr. Krishna Kumari Challa on Sunday

Ant brood signal deadly infection in altruistic self-sacrifice

Terminally ill ant pupae emit specific non-volatile odor signals that prompt worker ants to remove and disinfect them, preventing pathogen spread within the colony. This targeted signaling occurs only when infections are uncontrollable, ensuring colony health while minimizing unnecessary sacrifice, and parallels immune responses in multicellular organisms.

Sylvia Cremer, Altruistic disease signalling in ant colonies, Nature Communications (2025). DOI: 10.1038/s41467-025-66175-z. www.nature.com/articles/s41467-025-66175-z

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