Last Week in Science (26th Nov 2023)

The Head Tilt

Are you a dog parent or just that person who watches a lot of dog videos on Instagram. If the answer is yes, then this story is for you. As a dog parent you would have seen your dogs tilting their heads to one side and  would have wondered what they mean by it and whether it is another tactic to get to eat your food. You would have also searched the internet for what this behaviour could mean, and would have found answers. Now the answer has come from the researchers from the Eötvös Loránd University, Hungary, in Europe, who studies 'gifted dogs'. Yes, how can any dog be better than your dog, but let us just humor the researchers. These gifted dogs which were all border collies - could remember names of more than 10 toys and would bring them when told the name. Most dogs can remember no more than two. 

The interesting part comes when the researchers saw all these dogs tilting their heads just after hearing the word before they would go and search the toy which they know by that word. The researchers think that the dogs might be visualizing the toy on hearing the name or paying close attention during the head tilt. So, the next time you see your dog giving the head tilt, wonder what all can be happening inside that pup's brain. And no they haven't started any word training classes yet! 


Can we control our eating speed?

Have you wondered when you can't stop munching those chips what would be happening inside your body? Not a direct answer but a related answer has been found in a recent study. 

It has been shown that nerves in the gut convey the message to the brain and this helps you known when you are full. Such studies have been done in mice that were under anaesthesia so we don't know how their bodies will respond when they are being fed in an awake
state. Researchers at the University of California, San Francisco, studied mice in an awake state. What was special about these mice was that their brain region that receives the signal from the gut could be controlled - switched on or off by a method known as optogenetics, and also seen when the region is active. 

What the researchers found was the mice feed on a sweet and tasty liquid meal a specific neural circuit (made of PRLH neurons) switches on as the mice licks but shuts down the second the mice stops licking the meal. So, it switches on and off with the licking of the mice. While when the mice were given this sweet liquid directly in their stomach, the circuit switches on slowly and remains active until after feeding was stopped. This observation means that the brain can distinguish whether the signal is coming from the mouth or the gut. What was interesting this brain circuit did not switch on in the mice who cannot taste sweetness. Now, when this PRLH circuit was kept on the speed of the mice feeding/licking reduced.

A different brain circuit (GCG) was seen to be involved in giving the signal that the stomach is now full as they switch on minutes after the meal is consumed. It is interesting to see how different brain circuits control information coming from the mouth or the stomach and one is responsible for how fast you eat and the other for how much you eat. So, maybe if we keep that GCG circuit on maybe we can stop munching on those chips.


Greetings from far beyond

Cosmic rays are high energy particles, remember the dual nature of light and subatomic particles, that come in contact with Earth's atmosphere. The cosmic rays are formed by explosions, collisions and certain other physical phenomena that happen in space. It is a search ground for humans to discover new subatomic particles. Remember atom is further made up of subatomic particles like electrons and protons. 

The energy that is contained in these particles are measured in electron volts (eV). The typical energy levels of subatomic particles on Earth are close to Mega electron volts (100,000 electron volts). And the energy in the cosmic rays are close to 10 raise to power 18 (1 followed by 18 zeros) eV called as exa electron volts (EeV). It is rare that a subatomic particle that has an energy greater than 100 EeV comes to greet us. The last time it happened was in 1991 when the greatest high energy particle - which was named as 'Oh My God' particle was observed. It had an energy level of 320 EeV. 

We were greeted by an energy particle of 240 EeV this time, and the researchers at Osaka Metropolitan University in Japan who found it named it on a Sun goddess - Amaterasu. This doesn't mean that the particle came from the Sun. While the cosmic rays coming from the Sun were the first ones to be observed, we now can identify the origin of other cosmic rays coming from far beyond the Sun. But this time, it is not known where this particle came from. According to the researchers' calculation the particle seems to be coming from a space where there are hardly any galaxies. Astronomers think that it might be a new physical phenomenon that has created this particle and that could be the reason why they cannot find the origin of the Amaterasu particle.