“Switch” discovered in the brain of mice that enables and disables hunger

Usually, stress is considered as one of the factors that lead to gaining weight because it is linked to a greater desire for hunger. However, a group of researchers from the University of Texas Health Science Center found that by increasing the stress levels in the brain circuits of mice it is possible to decrease the desire to eat by the rodents themselves.

Such a discovery could be useful in particular for those people subjected to anorexia nervosa, an eating disorder for which they avoid food or eat very small amounts. As Qingchun Tong, senior author of the study and professor at McGovern Medical School of UTHealth, explains, researchers identified a part of the brain in mice “that controls the impact of eating-related emotions.”

The same researchers think they are the first to have demonstrated the existence of this neurocircuit that regulates both stress and hunger. This neurocircuit connects two parts of the brain in mice, the paraventricular hypothalamus and the ventral lateral septum. The first is an area linked to food, the second is an emotional area.

The same neurocircuit seems to act as an on / off switch. Activating it, there was an increase in anxiety and stress and in parallel a decrease in appetite. By turning it off, anxiety and stress decreased and hunger increased.

Intraneural electrode bypasses the eye and provides visual signals to the brain

A device that “bypasses” the entire eyeball by sending messages to the brain of the blind was developed by researchers from EPFL in Switzerland and the Scuola Superiore Sant’Anna in Italy. The device directly stimulates the optic nerve with a new generation electrode called OpticSELINE. In the study, published in Nature Biomedical Engineering, positive findings have already been reported in experiments performed on rabbits.

The intraneural stimulation device is based on the production of phosphenes through which users can “see” the light bypassing the eye. The basic technology is already part of different types of retinal implants but these prosthetic devices are not suitable for all pathologies. For example, people with retinitis pigmentosa usually cannot benefit from this technology.

On the other hand, other devices that act directly on the brain, such as brain implants that directly stimulate the visual cortex, are still considered risky. This new intraneural solution can in a certain sense be considered as a middle way that collects the positive aspects of both technologies.

In addition to providing visual information useful to patients, these devices are stable and, once implanted, are less likely to move. The electrodes, in fact, are positioned through a surgical operation around and through the nerve.

Researchers have also developed an algorithm to decode cortical signals because each electrode-induced stimulation induces a specific and unique model in the brain.

Diego Ghezzi, one of the authors of the study, states: “For now, we know that intraneural stimulation has the potential to provide visual information models. It will take feedback from patients in future clinical trials to develop these patterns. From a purely technological perspective, we could do clinical trials tomorrow.”

Melting of Greenland glaciers will require more Americans to move more inland

A statement released several days ago by Andrew Yang, an American philanthropist and politician who has always been attentive to the environment, has led to a great deal of discussion. According to Yang, Americans living along the coasts should already begin to retreat inland or into higher areas in view of the rising sea level caused by global warming and in particular by melting Arctic ice.

According to Young, it is already too late to stop climate change and it is time for Americans to start settling near the hills as long as there is time to do things neatly. The idea was supported by an intervention on the CNN site of Josh Willis, NASA oceanographer, who clearly states that by the end of this century and by the next many meters of hinterland will be lost near the coasts.

The melting of the Greenland glaciers will be the main cause of the raising: “There is enough ice in Greenland to raise the sea level by 7.5 meters,” says the researcher, suggesting that the enormous volume of ice, even if it melts in part, it will cause devastating damage to the shores of the entire planet.

Together with his research team, Willis has in fact collected alarming data regarding Greenland, particularly in the last few months when various heatwaves hit the northernmost areas of the Americas, the United States and Asia. The surface temperature of Greenland is warming up and this is transforming this piece of land, once entirely covered by ice, into a “mess full of slush.”

The massive ice cap of this huge piece of land is weakening and that means problems for the whole world, not just for Americans.

Also of great concern are the sea temperatures that scientists have measured, particularly near the Helheim glacier, a glacier located on the east coast of Greenland that has unusually warm water all its depth, up to 2000 meters below the surface, which is above feeding the same melting ice.

Humans arrived in Mongolia 45,000 years ago and perhaps joined Denisovani

A group of researchers from the University of California at Davis shows, through a study presented in Scientific Reports, that humans arrived in today’s steppe Mongolia 10 years earlier than previously calculated. Following the discovery of various stone tools in Mongolia, the researchers calculated that the advent of the first human beings in this area must have occurred 45,000 years ago, 10,000 years earlier than previously estimated.

Furthermore, the same study shows the actual possibility of an encounter between these human beings and the Denisovans, our mysterious cousins ​​who died out thousands of years ago. This same meeting could have been the main one that allowed Homo sapiens to take advantage of the particular geniuses of the Denisovans, which allowed our ancestors to be able to live and settle in high-altitude areas such as those of the Tibetan plateau.

The excavations were conducted by Nicolas Zwyns, a professor of anthropology and the lead author of the study, from 2011 to 2016 on the site called Tolbor-16 which is located along the Tolbor river, in the northern Hangaj mountains, in northern Mongolia. The objects found are 826 thick stone artifacts with long and regular blades, among other things similar to many others found in Siberia and China, which indicates the spread of human beings on a large scale in this period in Asia.

“The most intriguing aspect is that they are produced in a complicated but systematic way – and that this seems to be the signature of a human group that shares a common technical and cultural background,” says Zwyns himself regarding these correlations. Precisely this correlation allowed researchers to exclude that these objects had been created by Neanderthals or by the Denisovans themselves, information that they could not have acquired since no human remains were found on the site.

Other findings, for example related to grass and other organic matter of medium-sized cattle, especially sheep and goats as well as horses, have then made it clear that this area must have had a warmer and wetter period that made this region, normally cold and dry, more hospitable and more suitable also for grazing animals.

Scientists find how the cave bears became extinct in the last ice age

What happened to the cave bear, one of the largest species of mammals extinct by the end of the last ice age? This is a question that has never had definite answers but now a team of researchers from various European institutions, including the University of Zurich, suggests what could be the solution to the riddle.

In a study published in Scientific Reports, the researchers deduce that it was not the climatic effects of the ice age itself that made these bears extinct thousands of years ago, but it was humans.
Analyzing the mitochondrial DNA of 59 remains of cave bears from various European areas, the researchers learned that the populations of these animals began to fall in number before the beginning of the last ice age, or 40,000 years ago.

Furthermore, the same researchers deduced that the bears of previous generations had already managed to overcome the other ice ages without significant population decreases. At the same time we know that modern humans began to populate the areas in which these bear populations lived about 40,000 years ago, all information that suggests that it was precisely the arrival of modern humans to decree its end.

The same researchers also confirmed that in these times even Neanderthals lived in these areas. However, the latter had lived with cave bears for tens of thousands of years and it is therefore unlikely that they were responsible for extinction. This may also mean that modern humans had much more effective and lethal hunting techniques than Neanderthals.

Cave bears were hunted not only for food but also for furs or to eliminate potential competitors in the use of the caves themselves as a dwelling.

Ever warmer winters are changing the structure of the Black Sea

According to a new study published in the Journal of Geophysical Research, the climate changes that are leading to global warming are changing the structure of the Black Sea. The research is important because it could be useful to understand what could happen to the oceans of the world in the future if global warming continues at today’s pace.

Specifically, researcher Emil Stanev, an oceanographer at the Helmholtz-Zentrum Center for Materials and Coastal Research in Geesthacht, Germany, found that the warmest winters are heating the middle layer of the Black Sea, an area known as the layer intermediate cold. This is leading to a mixing of the same cold intermediate layer with the other two layers of water, the upper one oxygenated and the lower one devoid of oxygen.

According to the study, the temperature of this layer has warmed by 0.7 ° C over the past 14 years. The infiltration of the central layer in the two neighboring layers could lead to potentially unpredictable impacts on all life forms present in the Black Sea. In particular, this “restructuring” could lead to various corrosive or harmful chemicals, such as sulphides, to move from the bottom of the sea to the surface, which would affect not only marine life but also tourism.

The study could be important to understand how the same changes are occurring in the oceans: studying the latter, which are huge bodies of water without interruption, can sometimes be difficult for scientists who often prefer to study limited regional water masses, as can be that of the Black Sea.

Supernova that completely destroys the star discovered by astronomers

A type of supernova that can completely annihilate the star without leaving any traces was discovered by a group of researchers who used data from the European Space Agency’s Gaia satellite.

They studied a supernova, first discovered 14 November 2016 and called SN 2016iet. They first discovered that the star that caused the explosion lived in an isolated region, a region where few stars formed. As evidence of this, there was the weak emission of hydrogen coming from the same supernova position — an unusual thing for such a massive star.

They then discovered other strange characteristics: the long duration of the explosion, the great energy emitted and the unusual chemical traces emitted by the explosion relatively poor of heavier elements, things for which there are no similar sightings in the astronomical literature. In the study, published in the Astrophysical Journal, other features of the star that exploded and gave birth to the supernova are described.

It had 200 times the mass of our Sun. These are very large and massive stars that live little (life can be estimated in millions of years) and that usually die emitting large amounts of heavy metals into the surrounding space. The core, however, collapses and becomes a neutron star or black hole.

In these supernovae, the core that collapses produces large amounts of gamma rays. This, in turn, causes a large production of particle pairs and antiparticles on the run, and this leads to a catastrophic thermonuclear explosion that practically annihilates the entire star, including the nucleus.

The theory concerning supernovae with couple instability predicted that these explosions could only occur in environments that were poor in metal, such as dwarf galaxies or the primordial universe. And this discovery confirms it: the supernova SN 2016iet has, in fact, occurred in a metal-dwarf galaxy at a billion light-years away from us.

“This is the first supernova in which the mass and metal content of the exploding star falls within the range predicted by theoretical models,” reports Sebastian Gomez, a researcher at the Center for Astrophysics and one of the authors of the study.