Click, click, crazy
While many of us may find the sounds of chewing or breathing off-putting, for some they're unbearable - and new research has shown their brains are going into overdrive.
A US team of scientists have revealed new insights into the physical basis for people suffering from a condition called misophonia, a disorder where they have a hatred of sounds such as eating, chewing or repeated pen clicking.
Called "trigger sounds" by the misophonia community, the response can be an immediate and intense fight or flight feeling.
In the journal Current Biology, the researchers from Newcastle University report the first evidence of clear changes in the structure of the brain's frontal lobe in sufferers of misophonia and also report changes in the brain activity.
Brain imaging revealed that people with the condition have an abnormality in the emotional control mechanism which causes their brains to go into overdrive on hearing trigger sounds.
Researchers also found brain activity originated from a different connectivity pattern to the frontal lobe.
This was normally responsible for suppressing the abnormal reaction to sounds.
Further, they revealed that trigger sounds evoked a heightened physiological response with increased heart rate and sweating in people with misophonia.
"For many people with misophonia, this will come as welcome news as for the first time we have demonstrated a difference in brain structure and function in sufferers," said study leader Dr Sukhbinder Kumar.
"Patients with misophonia had strikingly similar clinical features and yet the syndrome is not recognised in any of the current clinical diagnostic schemes.
"This study demonstrates the critical brain changes as further evidence to convince a sceptical medical community that this is a genuine disorder."
How frogs use 'reversible saliva'
A frog uses its whip-like tongue to snag its prey faster than a human can blink, hitting it with a force five times greater than gravity.
How does it hang on to its meal as the food rockets back into its mouth?
A new US study finds the tongue's stickiness is caused by a unique "reversible saliva" in combination with a super soft tongue.
A frog's saliva is thick and sticky during prey capture, then turns thin and watery as prey is removed inside the mouth.
The tongue, which was found to be as soft as brain tissue and 10 times softer than a human's tongue, stretches and stores energy much like a spring.
This combination of spit and softness is so effective that it provides the tongue 50 times greater work of adhesion than synthetic polymer materials such as sticky-hand toys.
Georgia Institute of Technology researchers filmed frogs eating crickets in super-slow motion to better understand the physics of the tongue.
They also collected saliva samples and poked the tissue to measure softness.
"The tongue acts like a bungee cord once it latches onto its prey," said study leader Alexis Noel.
"It deforms itself as it pulls back toward the mouth, continually storing the intense applied forces in its stretchy tissue and dissipating them in its internal damping."
This tissue damping, Noel said, is much like a car's shock absorbers.
The tongue's softness also allows it to change shape during contact and immediately afterward while retracting.
The other vital component of the capturing process is the frog's versatile saliva.
"There are actually three phases," Noel said.
"When the tongue first hits the insect, the saliva is almost like water and fills all the bug's crevices.
Then, when the tongue snaps back, the saliva changes and becomes more viscous -- thicker than honey, actually - gripping the insect for the ride back.
"The saliva turns watery again when the insect is sheared off inside the mouth."
Little shop of horrors
To the average plant-eating human, the thought of a plant turning the tables to feast on an animal might seem like a lurid novelty.
Now, science is showing just how remarkable these macabre traits really are.
A new study probes the origins of carnivory in several distantly related plants - including the Australian, Asian and American pitcher plants, which appear strikingly similar to the human (or insect) eye.
Although each species developed carnivory independently, the research concludes that the biological machinery required for digesting insects evolved in a strikingly similar fashion in all three.
The findings hint that for a plant, the evolutionary routes to carnivory may be few and far between.
"It suggests that there are only limited pathways for becoming a carnivorous plant," University at Buffalo biologist Victor A. Albert said.
"These plants have a genetic tool kit, and they're trying to come up with an answer to the problem of how to become carnivorous.
"And in the end, they all come up with the same solution."
The path to carnivory was indeed remarkably similar for the three species examined - Cephalotus follicularis (the Australian pitcher plant, related to starfruit), Nepenthes alata (an Asian pitcher plant related to buckwheat) and Sarracenia purpurea (an American pitcher plant related to kiwifruit).
A genetic analysis, which included sequencing the entire genome of Cephalotus, found strong evidence that during their evolution into carnivores, each of these plants co-opted many of the same ancient proteins to create enzymes for digesting prey.
Over time, in all three species, plant protein families that originally assisted in self-defence against disease and other stresses developed into the digestive enzymes we see today, genetic clues suggest.
These enzymes include basic chitinase, which breaks down chitin - the major component of insects' hard, exterior exoskeletons - and purple acid phosphatase, which enables plants to obtain phosphorus, a critical nutrient, from victims' body parts.
Enzymes in a fourth carnivorous species, the sundew Drosera adelae, a relative of Nepenthes that is not a pitcher plant, also appeared to share this evolutionary road.
Scientists stumble upon 'stray' black hole
Scientists analysing the strange gas motion of an extraordinarily fast-moving cosmic cloud in a corner of our galaxy the Milky Way have revealed hints of a wandering black hole hidden in the cloud.
This result marks the beginning of the search for quiet black holes; millions of such objects are expected to be floating in the Milky Way although only dozens have been found to date.
It is difficult to find black holes, because they are completely black.
In some cases black holes cause effects which can be seen.
For example if a black hole has a companion star, gas streaming into the black hole piles up around it and forms a disk.
The disk heats up due to the enormous gravitational pull by the black hole and emits intense radiation.
But if a black hole is floating alone in space, no emissions would be observable coming from it.
A Japanese research team used the ASTE Telescope in Chile and the 45m Radio Telescope at Nobeyama Radio Observatory to observe molecular clouds around the supernova remnant W44, located 10,000 light-years away from us.
Their primary goal was to examine how much energy was transferred from the supernova explosion to the surrounding molecular gas, but they happened to find signs of a hidden black hole at the edge of W44.
During the survey, the team found a compact molecular cloud with enigmatic motion.
This cloud, named the "Bullet," has a speed of more than 100 km/s, which exceeds the speed of sound in interstellar space by more than two orders of magnitude.
Further, the cloud, with the size of two light-years, moved backward against the rotation of the galaxy.
"Most of the Bullet has an expanding motion with a speed of 50 km/s, but the tip of the Bullet has a speed of 120 km/s," said study leader Masaya Yamada, of Japan's Keio University.
"Its kinetic energy is a few tens of times larger than that injected by the W44 supernova. It seems impossible to generate such an energetic cloud under ordinary environments."
Theoretical studies have predicted that 100 million to 1 billion black holes should exist in the Milky Way, although only 60 or so have been identified through observations to date.
The team expects to disentangle two possible scenarios and find more solid evidence for a black hole in the Bullet with higher resolution observations using a radio interferometer.