Science News
Headlines
. A 168-million-year-old stegosaurs fossil discovered
. How do we have oxygen in Earth's atmosphere?
. Can you read people's minds?
. Coming up: Historic treaty on plastic waste
. Switching off Specific Brain Cells Protects Against Stress

Read more about some of these issues below.

A 168-million-year-old stegosaurs fossil discovered
A stegosaur is a type of dinosaur. Dinosaurs went extinct more than 65 million years ago, but there have been several dinosaur remains that have been found all over the world. Recently, a fossil of a stegosaur was found in the area of Chongqing in southwestern China. It has been named Bashanosaurus primitivus. Bashan refers to the ancient name for that area, and primitivus is Latin for first. The fossil is one of the oldest ever discovered and could help us to understand more about this dino.
What is a fossil? When an animal dies, or is buried by accident beneath sand or mud, it sometimes forms a fossil. Over time, more and more more layers of sand build up on top of the animal. Due to the weight of the layers above, the sand around the skeleton (which is all that is left of the animal) is compressed so much that it begins to turn into rock. Soon the bones themselves dissolve in the water that seeps through this sand which is now turning into rock.
Since the water also contains minerals such as silica and calcium, the space left behind when the bones dissolve is now filled with this residual mineral. This mineral also gets compressed over time and becomes rock. Since these mineral deposits replaced the bones of the animal, the rock that forms is in the shape of the original animal (actually of its skeleton). This is called a fossil. If the fossil is well-preserved, the original bones of the animal can be clearly identified. Since the whole process takes millions of years, fossils are very useful to study how the bones of animals have evolved over time by comparing them with the skeletons of similar modern day animals. (Many animals such as dinosaurs are completely extinct. So when you see pictures of them with yellow or greenish skin, this is just a guess. We only know what their skeleton was like).
The stegosaur is one of the well-known dinos, and was popularised in the movie Jurassic Park. About 6 m long, with jutting armoured backplates, and a spiked tail, its long neck and almost comically small head makes it easy to recognise. Although they looked scary, they were plant eating animals which were present in very large numbers on Earth from more than 150 million years ago. Their fossils have been found on all continents (except Australia and Antarctica). However it is very rare to find a complete fossil and so it has been difficult for scientists studying these animals (calledpalaeontologists) to come up with a complete Stegosaur family tree.
Now, researchers in China have discovered a stegosaur fossil that has bones from the back, shoulder, thigh, feet, and ribs of the animal, as well as several armour plates. They have dated this to 168 million years old, making it the oldest ever found in Asia. This fossil was rather small (less than 3 m long) with smaller armour plates and perhaps was not full-grown. Using this find, scientists have found that perhaps stegosaurs may have originated in Asia.

How do we have oxygen in Earth's atmosphere?
We know that our atmosphere is mostly nitrogen and contains about 20% of oxygen. This is what helps us to breathe; in fact, every life form needs oxygen to live. Plants use up carbon dioxide and give out oxygen during photosynthesis, which is their energy-producing mechanism. Today, the amount of oxygen in the atmosphere is balanced between those of us who use it up an the plants which produce it. Before plants evolved and so before photosynthesis took place, there was hardly any free oxygen in the atmosphere. So, how did this oxygen get into Earth's atmosphere in the first place?
Scientists have studied the history of this process by looking at remains of plants from long ago. Our earth is about 4.5 billion years old. For the first half of its life, there was hardly any oxygen in the air. Sometime about 2.3 billion years ago, there was a sudden build-up of oxygen in the air and this excess has remained to this day. This is called the Great Oxygenation event. In fact, scientists think there were two occasions when this happened: once about 2 billion years ago, and once about a billion years ago.
Recently, some scientists from the MIT, USA, suggested a possible mechanism for this event. They said that certain microbes in the sea interacted with minerals in ocean sediments in such a way that the oxygen was no longer used up and began to accumulate in the air.
A lot of organic matter in the ocean is broken down by microbes. Such microbes were present in the ocean many billions of years ago. All life forms are made of carbon. Typically, this carbon is broken down by oxygenation, using up oxygen to produce carbon dioxide. Suppose that long ago, the microbes were unable to fully break down this organic matter. They worked out that such "partially oxidised organic matter" called POOM, would become sticky. Then it would start to bind to minerals present in the sediment at the bottom of the ocean, thus preventing its further oxydation. Once such a process occurred, it would build up, leaving more and more excess oxygen to build up in the air.
The scientists actually found a group of microbes that actually does this even today. These microbes belong to the bacterial group called SAR202 and they have a gene that produces an enzyme called Baeyer-Villiger monooxygenase, or BVMO. This BVMO helps to partially oxidise matter. They found that ancestors of this microbe were indeed living so many billions of years ago. Whenever there was an increase in oxygen levels in the atmosphere, the number of species carrying this gene was found to also increase substantially.
To confirm this hypothesis will require far more follow-up, but this is the first time that scientists have proposed such a movel idea for the Great Oxygenation event, without which none of us would be here today.

Can you read people's minds?
Researchere in Osaka University in Japan have achieved something incredible: they have found a way to read your mind! Even if the person is looking at some other picture, they are able to read back what you are actually imagining at that time, and not just what you are seeing! They do this by reading your brain wave patterns.
What we are seeing around us is interpreted in our brains. This visual information can be detected by a technique called electrocorticogram, which detects patterns of electrical activity in the brain. As we pay attention to different events, or think about something else, these patterns keep changing.
Scientists worked with epilepsy patients who already had electrodes implanted in their brains. The patients were shown some picture and then told to think of something completely different. For instance, they were told to imagine a “landscape,” “human face,” or “word”. when the patients looked at the pictures they were given, a certain pattern of brain waves was seen. But when they were shown the picture and asked to imagine something else, a completely different pattern was recorded. 
The scientists also recorded how long it took for the brain waves to change from that for the given picture to the one for the imagined picture. They found that this depended on the image they were instructed to think about. If it was just a word, the brain wave changed quite quickly, but if they were asked to imagine a landscape, the time taken was very different. This could be because very different parts of the brain are involved in thinking about a word or thinking about a landscape.
From looking at the pattern of brain waves, the scientists could infer what the patients were imagining with high accuracy. This could be used to develop a communication device for severely paralysed patients, who cannot communicate by speech. Already there are devices in the market that use hand or finger or eyelid movements to interpret the patient's thoughts or wishes. But with paralysed patients there isa danger that they may lose muscle control as well. So Similar devices already used by an imagery-based device could be highly valuable.

Coming up: Historic treaty on plastic waste
Recently, world leaders met in Nairobi, Kenya, to share their concern on the growing pollution due to plastic waste around the world. They have come to a historic decision. Environment ministers and representatives from 173 countries have agreed to develop a legally binding treaty on plastics, which will be negotiated in the next two years. It has been described by the head of the UN Environment Programme (UNEP) as the most important multilateral environmental deal since the Paris climate accord in 2015.
Plastic consumption is about two and a half times more per person in developed countries like the USA than in developing countries like India. In the last 70 years, about 9.2 billion tons of plastic has been produced. Of this, about 7 billion tons are now just waste! Use and throw plastic bags, packaging material, plastic cups and spoons, and a whole lot of plastic used in industry, have now been mostly dumped in landfills. These plastic are not bio-degradable and will lie around for ever. Some of them will be shredded into smaller pieces and get washed off into the sea or lakes and rivers. Here they are ingested by fish, or on land, they get into the food as micro-plastics. Cattle and deer are being found dead with large quantities of plastic in their stomach and intestines. Plastic is even there in the air we breathe due to large amounts of it being regularly burned.
While some plastic is being recycled (and non-recyclable plastic being banned), still a lot of it is in use today, adding to the already huge amount piling up on land and in the sea. As Norway’s minister for climate and the environment, Espen Barth says, “Plastic pollution has grown into an epidemic. With today’s resolution we are officially on track for a cure.”
What does the agreement plan to do?
. Persuade countries and large businesses to shift away from single-use plastics
. to mobilise private finance and remove barriers to investments in research in related areas
. to tackle not just plastic waste, but the production and design of new plastic
. to recognise for the first time, waste pickers and the role of indigenous peoples in helping to segregate and recycle plastics.
An intergovernmental negotiating committee has been tasked with drafting and ratifying the treaty. It will start work this year and aims to finish by 2024.
Christina Dixon, the deputy ocean campaign lead at the Environmental Investigation Agency, said, “Fundamentally, the plastics tap must be turned off if we are serious about tackling the problem.” 
No wonder then, the central artwork at the Nairobi summit venue was made with rubbish from Kibera slum by the artist Benjamin von Wong, urging people to ‘turn off the plastic tap’. See the picture.
Sources: BBC Science News, MIT News: https://news.mit.edu/2022/great-oxygenation-event-microbes-0314, https://neurosciencenews.com/imagination-brain-wave-20212/, Guardian News, https://www.theguardian.com/environment/2022/mar/02/world-leaders-agree-draw-up-historic-treaty-plastic-waste