Comment

Comment by Dr. Krishna Kumari Challa on November 22, 2023 at 12:29pm

The World Is Running Out of Male Sea Turtles

Green sea turtles are already an endangered species, mainly due to humans hunting them, harvesting their eggs, degrading their habitats, or entangling them in garbage (fishing nets) of some kind.

But they also face another, more insidious threat from people: the loss of male hatchlings from the species.

You probably already know that this is partly caused by rising temperatures due to climate change – but a new study has now unveiled another human-caused problem driving this trend.

Certain pollutants may promote feminization in sea turtles. New research work  shows that the risk of extinction due to a lack of male green sea turtles may be compounded by contaminants that may also influence the sex ratio of developing green sea turtles, increasing the bias towards females.

Green sea turtles (Chelonia mydas) have a vast geographical range, inhabiting tropical, subtropical, and temperate regions of the Atlantic, Pacific, and Indian oceans, as well as the Mediterranean Sea.

Male hatchlings are now heavily outnumbered by females overall, although the degree of imbalance varies in different parts of their range. In some warmer places like the northern Great Barrier Reef, researchers say, hundreds of female turtles are now born for every male.

That's because sea turtles use temperature-dependent sex determination, meaning an embryo's sex is determined by sand temperatures around its egg in the nest, with warmer sand favoring females. As temperatures rise around the world, male hatchlings are growing scarce. But that's not the only factor involved in determining sex, the latest research suggests.

Part 1

Comment by Dr. Krishna Kumari Challa on November 22, 2023 at 11:34am

Gut microbes help alleviate constipation

Scientists have identified the genes in the probiotic Bifidobacteria longum responsible for improving gut motility. A research team reporting November 21 in the journal Cell Host & Microbe found that B. longum strains possessing the abfA cluster of genes can ameliorate constipation through enhanced utilization of an indigestible fiber called arabinan in the gut.

The researchers established the causal link between a genetic variant—the abfA cluster—to the key functional difference of probiotic B. longum in multiple model organisms, including mice and humans, and provided mechanistic and ecological insights into how a single gene cluster can affect the gut motility of hosts through arabinan metabolism.

Peter Kuffa et al, Fiber-deficient diet inhibits colitis through the regulation of the niche and metabolism of a gut pathobiont, Cell Host & Microbe (2023). DOI: 10.1016/j.chom.2023.10.016

----

Solar panels vs planting forests: Which reduces climate change faster?

Photovoltaic fields outperform afforestation as a global climate-change mitigation strategy, according to a study published in the journal PNAS Nexus.

Comment by Dr. Krishna Kumari Challa on November 22, 2023 at 11:18am

How bloodstain 'tails' can point to significant, additional forensic details

Most of us know that evidence left at a crime scene, such as blood, can often reveal information that is key to investigating and understanding the circumstances around a crime—and that scientific methods can help interpret that information.

In the journal Physics of Fluids, a group of scientists   demonstrated how bloodstains can yield even more valuable details than what is typically gathered by detectives, forensic scientists, and crime scene investigators. By examining the protrusions that deviate from the boundaries of otherwise elliptical bloodstains, the researchers studied how these "tails" are formed. The article is titled "Bloodstain tails: Asymmetry aids reconstruction of oblique impact".

These protrusions are typically only used to get a sense of the direction that the drop traveled, but are otherwise neglected.

In fact, previous studies have primarily focused on larger blood drops falling vertically on flat surfaces or on inclined surfaces where gravity can reshape and obscure the tails. By contrast, the new study involved a series of high-speed experiments with human blood droplets with diameters of less than a millimeter impacting horizontal surfaces at various angles.

This new study shows that  the precise flow that determines the tail length differs from the flow responsible for the size and shape of the elliptical portion of the stain. "In other words, the tail lengths encompass additional independent information that can help analysts reconstruct where the blood drop actually came from."

Indeed, the tail length can reflect information about the size, impact speed, and impact angle of the blood drop that formed the stain. When measured for several blood stains in a stain pattern, the trajectories of the drops can be backtracked to their presumed origin.

Incorporating tail length into standard bloodstain analyses will produce more robust evidentiary information.

"Knowing the origin of the blood stains at a crime scene can help detectives determine whether a victim was standing or sitting, or help corroborate or question a witness's testimony.

Garam Lee et al, Bloodstain tails: Asymmetry aids reconstruction of oblique impact, Physics of Fluids (2023). DOI: 10.1063/5.0170124

Comment by Dr. Krishna Kumari Challa on November 22, 2023 at 11:06am

Unearthing how a carnivorous fungus traps and digests worms

A new analysis sheds light on the molecular processes involved when a carnivorous species of fungus known as Arthrobotrys oligospora senses, traps and consumes a worm. 

A. oligospora usually derives its nutrients from decaying organic matter, but starvation and the presence of nearby worms can prompt it to form traps to capture and consume worms. A. oligospora is just one of many species of fungi that can trap and eat very small animals.

When A. oligospora first senses a worm, the findings suggest, DNA replication and the production of ribosomes (structures that build proteins in a cell) both increase. Next, the activity increases of many genes that encode proteins that appear to assist in the formation and function of traps, such as secreted worm-adhesive proteins and a newly identified family of proteins dubbed "trap enriched proteins" (TEP).

Finally, after A. oligospora has extended filamentous structures known as hyphae into a worm to digest it, the activity is boosted by genes coding for a variety of enzymes known as proteases—in particular, a group known as metalloproteases. Proteases break down other proteins, so these findings suggest that A. oligospora uses proteases to aid in worm digestion.

These findings could serve as a foundation for future research into the molecular mechanisms involved in A. oligospora predation and other fungal predator-prey interactions.

Lin H-C, de Ulzurrun GV-D, Chen S-A, Yang C-T, Tay RJ, Iizuka T, et al. (2023) Key processes required for the different stages of fungal carnivory by a nematode-trapping fungus. PLoS Biology (2023). DOI: 10.1371/journal.pbio.3002400

Comment by Dr. Krishna Kumari Challa on November 22, 2023 at 11:00am

Babies as young as four months show signs of self-awareness: Study

Babies as young as four months old can make sense of how their bodies interact with the space around them, according to new research.

The findings, published in Scientific Reports, shed new light on how self-awareness develops. Experts  showed babies a ball on a screen moving towards or away from them. When the ball was closest to them on the screen, the babies were presented with a 'touch' (a small vibration) on their hands while their brain activity was being measured.  The researchers found that from just four months old, babies show enhanced somatosensory (tactile) brain activity when a touch is preceded by an object moving toward them.

These findings indicate that even in the first few months of life, before babies have even learned to reach for objects, the multisensory brain is wired up to make links between what babies see and what they feel. This means they can sense the space around them and understand how their bodies interact with that space. This is sometimes referred to as peripersonal space.

Of course, humans do this all the time as adults, using our combined senses to perceive where we are in space and making predictions about when we will touch an object or not. But now that we know that babies in the early stages of their development begin to show signs of this, it opens up questions about how much of these abilities are learned or innate.

Visual objects approaching the body modulate subsequent somatosensory processing at 4 months of age, Scientific Reports (2023). DOI: 10.1038/s41598-023-45897-4

Comment by Dr. Krishna Kumari Challa on November 22, 2023 at 10:55am

High temperatures may have caused over 70,000 excess deaths in Europe in 2022

The burden of heat-related mortality during the summer of 2022 in Europe may have exceeded 70,000 deaths according to a study .

The authors of the study, published in The Lancet Regional Health—Europe, revised upwards initial estimates of the mortality associated with record temperatures in 2022 on the European continent. The study is titled "The effect of temporal data aggregation to assess the impact of changing temperatures in Europe: an epidemiological modelling study."

Ballester J et al, The effect of temporal data aggregation to assess the impact of changing temperatures in Europe: an epidemiological modelling study, The Lancet Regional Health—Europe (2023). DOI: 10.1016/j.lanepe.2023.100779

Comment by Dr. Krishna Kumari Challa on November 22, 2023 at 10:50am

A wearable robot that assists people with walking

In recent years, roboticists have introduced increasingly advanced systems, which could open exciting new possibilities for surgery, rehabilitation, and health care assistance. These robotic systems are already helping to improve the quality of life of many people with disabilities, as well as patients who suffered physical

trauma or underwent medical procedures.

Researchers recently introduced a new wearable robot designed to specifically assist humans who have difficulties walking due to aging, muscle weakness, surgeries or specific medical conditions. This robot, presented in a paper published in Science Robotics, was found to improve balance, while also reducing the energy spent while walking (the so-called metabolic cost). 

In contrast with other robotic systems for hip abduction assistance proposed in the past, the robot now created  focuses on the frontal plane. This is the frontal part of the human body, known to support movements and lateral stability while walking.

Juneil Park et al, Effect of hip abduction assistance on metabolic cost and balance during human walking. Science Robotics (2023). DOI: 10.1126/scirobotics.ade0876.

Comment by Dr. Krishna Kumari Challa on November 21, 2023 at 1:57pm

AWEsome Waves in Earth’s Airglow

Comment by Dr. Krishna Kumari Challa on November 21, 2023 at 12:31pm

What is a sonar pulse and how can it injure humans under water?
Light doesn't travel well underwater—even in clear waters, you can see perhaps some tens of meters. Sound, however, travels very well and far underwater. This is because water is much denser than air, and so can respond faster and better to acoustic pressure waves—sound waves.

Because of these properties, ships use sonar to navigate through the ocean and to "see" underwater. The word "sonar" stands for sound navigation and ranging.

Sonar equipment sends out short acoustic (sound) pulses or pings and then analyzes the echoes. Depending on the timing, amplitude, phase, and direction of the echoes the equipment receives, you can tell what's underwater—the seafloor, canyon walls, coral, fishes, and of course, ships and submarines.

Most vessels—from small, private boats to large commercial tankers—use sonar. However, compared to your off-the-shelf sonar used for finding fish, navy sonars are stronger.
The effects of sonar on divers
We don't hear well underwater—no surprise since we've evolved to live on land. Having said that, you would hear a sonar sound underwater (a mid-to-high pitch noise) and would know you've been exposed.
When it comes to naval sonars, human divers have rated the sound as "unpleasant to severe" at levels of roughly 150dB re 1 µPa (decibel relative to a reference pressure of one micro pascal, the standard reference for underwater sound). This would be, perhaps, very roughly 10km away from a military sonar. Note that we can't compare sound exposure under water to what we'd receive through the air because there are too many physical differences between the two.

Human tolerance limits are roughly 180dB re one µPa, which would be around 500m from military sonar. At such levels, humans might experience dizziness, disorientation, temporary memory and concentration impacts, or temporary hearing loss.
At higher received levels, closer ranges, or longer exposures, you might see more severe physiological or health impacts. In extreme cases, in particular, for impulsive, sudden sound (which sonar is not), sound can cause damage to tissues and organs.
What does sonar do to marine animals?
Some of the information on what noise might do to humans underwater comes from studies and observations of animals.

While they typically don't have outer ears (except for sea lions), marine mammals have inner ears that function similarly to ours. They can receive hearing damage from noise, just like we do. This might be temporary, like the ringing ears or reduced sensitivity you might experience after a loud concert, or it can be permanent.

Marine mammals living in a dark ocean rely on sound and hearing to a greater extent than your average human. They use sound to navigate, hunt, communicate with each other and to find mates. Toothed whales and dolphins have evolved a biological echo sounder or biosonar, which sends out series of clicks and listens for echoes. So, interfering with their sounds or impacting their hearing can disrupt critical behaviors.

Finally, sound may also impact non-mammalian fauna, such as fishes, which rely on acoustics rather than vision for many of their life functions.

https://theconversation.com/what-is-a-sonar-pulse-and-how-can-it-in...

Comment by Dr. Krishna Kumari Challa on November 21, 2023 at 12:06pm

World's richest 1% emit as much carbon as bottom two-thirds: report

The richest one percent of the global population are responsible for the same amount of carbon emissions as the world's poorest two-thirds, or five billion people, according to an analysis published Sunday by the nonprofit Oxfam International.

While fighting the climate crisis is a shared challenge, not everyone is equally responsible and government policies must be tailored accordingly, according to the report.

It says, the richer you are, the easier it is to cut both your personal and your investment emissions. You don't need that third car, or that fourth holiday, or you don't need to be invested in the cement industry." 

Climate Equality: A Planet for the 99%", was based on research compiled by the Stockholm Environment Institute (SEI) and it examined the consumption emissions associated with different income groups up to the year 2019.
Among the key findings of this study are that the richest one percent globally—77 million people—were responsible for 16 percent of global emissions related to their consumption.

That is the same share as the bottom 66 percent of the global population by income, or 5.11 billion people.
Source: 2023 AFP

• ‹ Previous
• 1
• …
• 310
• 311
• 312
• 313
• 314
• …
• 1080
• Next ›
• Page