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Can sound and light can propagate simultaneously ?

2021-06-14T09:49:00.006+05:30

Using an ultrafast transmission electron microscope, researchers from the Technion—Israel Institute of Technology have, for the first time, recorded the propagation of combined sound and light waves in atomically thin materials.

Single-layer materials, alternatively known as 2D materials, are in themselves novel materials, solids consisting of a single layer of atoms. Graphene, the first 2D material discovered, was isolated for the first time in 2004, an achievement that garnered the 2010 Nobel Prize. Now, for the first time, Technion scientists show how pulses of light move inside these materials.

Light moves through space at 300,000 km/s. Moving through water or through glass, it slows down by a fraction. But when moving through certain few-layers solids, light slows down almost a thousand-fold. This occurs because the light makes the atoms of these special materials vibrate to create sound waves (also called phonons), and these atomic sound waves create light when they vibrate. Thus, the pulse is actually a tightly bound combination of sound and light, called "phonon-polariton."
The scientists shone pulses of light along the edge of a 2D material, producing in the material the hybrid sound-light waves. Not only were they able to record these waves, but they also found the pulses can spontaneously speed up and slow down. Surprisingly, the waves even split into two separate pulses, moving at different speeds.
Source: Science Journal (2021), phys.org, Israel Institute of Tech

28 Trillion Tonnes of Ice Have Melted Since 1994, on Track With Worst-Case Scenarios

2021-01-31T18:29:00.000+05:30

All over the world the rate of ice melt is accelerating with climate change, on land and in water, in the northern hemisphere and the southern hemisphere.

Since 1994, satellite imagery has revealed over 28 trillion tonnes of ice have melted in Greenland and Antarctica, as well as the Arctic and Southern Oceans.

Together, the loss amounts to a 100-metre thick sheet of ice roughly the size of the United Kingdom. Meltwater from Arctic sea ice and the Antarctic ice sheet make up half of that mass.

"The ice sheets are now following the worst-case climate warming scenarios set out by the Intergovernmental Panel on Climate Change," says Thomas Slater who studies land and ice altimetry at the University of Leeds.

"Sea-level rise on this scale will have very serious impacts on coastal communities this century."

It's exactly what scientists have been warning us about for decades, and the reality is finally upon us with no signs of slowing down.

Over the course of the 23-year-long study period, researchers saw close to a 60 percent increase in the rate of global ice loss.

bove: According to the European Space Agency (ESA), "one trillion tonnes of ice can be thought of as a cube of ice measuring 10x10x10 kilometres". In this illustration, that ice cube, which the ESA says would be taller than Mount Everest, towers over New York City.

Just last year, floating ice cover in the Arctic Ocean hit its lowest extent since 1979 when satellite recordings began, and Antarctica experienced a melt event unlike anything experts had seen before.

The loss of Earth's ice is clearly speeding up and with horrifying results. As atmospheric temperatures continue to rise and ocean temperatures follow, melting sea ice and mountain glaciers across the globe are succumbing to climate change.

Satellite observations reveal glaciers are some of the hardest hit by climate change, especially those in Greenland, Alaska, and the southern Andes. Despite the fact that glaciers make up only 1 percent of Earth's total ice volume, researchers found they contributed almost a quarter of all global ice loss.

Between 1994 and 2017, satellite observations reveal 6.1 trillion tonnes of ice melted from mountain glaciers, 3.8 trillion tonnes were lost from the Greenland ice sheet, and 2.5 trillion tonnes disappeared from the Antarctic ice sheet.

Overall, that's 35 millimetres (1.4 inches) of sea level rise, and while southern ice has proved more resilient, it too is beginning to crumble.

Since 2012, the rate of ice loss in Antarctica has tripled when compared to the previous two decades, and this is mostly due to widespread glacier melt and thinning ice shelves.

Rising atmospheric temperatures have also begun to take their toll on floating ice, causing the oldest and thickest slabs to break up. While this type of melt doesn't directly contribute to sea level rise that doesn't mean it isn't a threat

"One of the key roles of Arctic sea ice is to reflect solar radiation back into space which helps keep the Arctic cool," explains Isobel Lawrence, who specialises in remote sensing of sea ice at the University of Leeds.

"As the sea ice shrinks, more solar energy is being absorbed by the oceans and atmosphere, causing the Arctic to warm faster than anywhere else on the planet. Not only is this speeding up sea ice melt, it's also exacerbating the melting of glaciers and ice sheets which causes sea levels to rise."

For every centimetre of sea level rise, experts predict a million people are in danger of being displaced. What's more, mountain glaciers are a critical source of freshwater for many local communities.

As the data rolls in, what scientists feared most is looking all the more likely.

If things continue in the same vein, some think there's a chance the Arctic could be virtually free of ice by 2035.

Other studies show Greenland's melting ice has already passed the point of no return.

The study was published in The Cryosphere.

Our Solar System Is Going to Totally Disintegrate Sooner Than We Thought

2020-12-25T18:42:00.008+05:30

Our Solar System Is Going to Totally Disintegrate Sooner Than We Thought

Although the ground beneath our feet feels solid and reassuring (most of the time), nothing in this Universe lasts forever.

One day, our Sun will die, ejecting a large proportion of its mass before its core shrinks down into a white dwarf, gradually leaking heat until it's nothing more than a cold, dark, dead lump of rock, a thousand trillion years later

But the rest of the Solar System will be long gone by then. According to new simulations, it will take just 100 billion years for any remaining planets to skedaddle off across the galaxy, leaving the dying Sun far behind.

Astronomers and physicists have been trying to puzzle out the ultimate fate of the Solar System for at least hundreds of years.

"Understanding the long-term dynamical stability of the solar system constitutes one of the oldest pursuits of astrophysics, tracing back to Newton himself, who speculated that mutual interactions between planets would eventually drive the system unstable," wrote astronomers Jon Zink of the University of California, Los Angeles, Konstantin Batygin of Caltech and Fred Adams of the University of Michigan in their new paper.

But that's a lot trickier than it might seem. The greater the number of bodies that are involved in a dynamical system, interacting with each other, the more complicated that system grows and the harder it is to predict. This is called the N-body problem.

Because of this complexity, it's impossible to make deterministic predictions of the orbits of Solar System objects past certain timescales. Beyond about five to 10 million years, certainty flies right out the window.

But, if we can figure out what's going to happen to our Solar System, that will tell us something about how the Universe might evolve, on timescales far longer than its current age of 13.8 billion years.

In 1999, astronomers predicted that the Solar System would slowly fall apart over a period of at least a billion billion - that's 10^18, or a quintillion - years. That's how long it would take, they calculated, for orbital resonances from Jupiter and Saturn to decouple Uranus.

According to Zink's team, though, this calculation left out some important influences that could disrupt the Solar System sooner.

Firstly, there's the Sun.

In about 5 billion years, as it dies, the Sun will swell up into a red giant, engulfing Mercury, Venus and Earth. Then it will eject nearly half its mass, blown away into space on stellar winds; the remaining white dwarf will be around just 54 percent of the current solar mass.

This mass loss will loosen the Sun's gravitational grip on the remaining planets, Mars and the outer gas and ice giants, Jupiter, Saturn, Uranus, and Neptune.

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this article was publish on sciencealert.com

Scientists Just Set a New World Record in Solar Cell Efficiency

2020-12-14T19:03:00.002+05:30

Scientists Just Set a New World Record in

Solar Cell Efficiency

Improving the efficiency of solar cells can make a huge difference to the amount of energy produced from the same surface area and the same amount of sunshine, and another world record has been beaten in the push for better yields.

Researchers have now hit an efficiency of 29.15 percent in the perovskite/silicon tandem solar cell category, which is just one of several different types of cells. There are currently a variety of different technologies in use to convert solar energy into electricity.

For this type of panel, the long-term target of more than 30 percent is now tantalisingly within reach. The latest lab tests edge ahead of the maximum 28 percent efficiency that perovskite/silicon cells have managed up to this point.

"Tandem solar cells that pair silicon with a metal halide perovskite are a promising option for surpassing the single-cell efficiency limit," write the researchers in their published paper. "We report a monolithic perovskite/silicon tandem with a certified power conversion efficiency of 29.15 percent."

Perovskite and silicon have actually been developed separately as semiconductor materials for solar panel use: silicon cells have been around for longer, and are currently the standard in solar farms around the world.

Perovskite is the up and coming new challenger, which scientists think could eventually eclipse silicon in terms of usefulness.

That's why scientists have long been experimenting with different perovskite compound combinations and adding other materials – silicon, in this case. The so-called tandem cell uses two semiconductors that can capture two different parts of the light spectrum, extending beyond infrared light (captured by silicon) into visible light too (captured by the perovskite compounds).

More good news is that putting perovskite and silicon together doesn't substantially add to the cost of making the panels. Keeping the price down is important for getting solar technology rolled out as far and as quickly as possible.

In this new research, the 29.15 percent efficiency record was managed with a 1 cm x 1 cm (0.4 inch x 0.4 inch) panel, so some serious scaling up will be required. The team says that should be possible, however. After 300 hours of simulated use, the tandem cell retained 95 percent of its original efficiency, which is another promising sign.

The new record was actually first reported earlier this year, though the peer-reviewed paper detailing the feat has just been published. The scientists used specially tweaked layer compositions for both connecting the electrode layer and keeping the two types of cell together in order to reach their new record.

It's another moment to celebrate, but the scientists aren't stopping: previous research suggests that tandem solar cell technology should be able to reach efficiency rates of well above 30 percent, and the team says "initial ideas for this are already under discussion".

The research has been published in Science.

China turns on nuclear-powered 'artificial sun'

2020-12-07T14:22:00.007+05:30

China successfully powered up its "artificial sun" nuclear fusion reactor for the first time, state media reported Friday, marking a great advance in the country's nuclear power research capabilities.

It uses a powerful magnetic field to fuse hot plasma and can reach temperatures of over 150 million degrees Celsius, according to the People's Daily—approximately ten times hotter than the core of the sun.

Located in southwestern Sichuan province and completed late last year, the reactor is often called an "artificial sun" on account of the enormous heat and power it produces.

"The development of nuclear fusion energy is not only a way to solve China's strategic energy needs, but also has great significance for the future sustainable development of China's energy and national economy," said the People's Daily.

Chinese scientists have been working on developing smaller versions of the nuclear fusion reactor since 2006.

They plan to use the device in collaboration with scientists working on the International Thermonuclear Experimental Reactor—the world's largest nuclear fusion research project based in France, which is expected to be completed in 2025.

Fusion is considered the Holy Grail of energy and is what powers our sun.

It merges atomic nuclei to create massive amounts of energy—the opposite of the fission process used in atomic weapons and nuclear power plants, which splits them into fragments.

Unlike fission, fusion does not create radioactive waste, and carries less risk of accidents or the theft of atomic material.

But achieving fusion is both extremely difficult and prohibitively expensive, with the total cost of ITER estimated at $22.5 billioN.

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Can artificial leaf power the world ?

2020-12-06T09:56:00.009+05:30

CAN ARTIFICIAL LEAF POWER THE WORLD?

We from sciences pills bring some interesting news for you. Scientists from Waterloo university Canada have come up with a new design for an artificial leaf. that means creating energy with a whole new way using a process which used by plants form millions of years I.e photosynthesis.

What is artifice leaf ?

Artificial leaf, a silicon-based device that uses solar energy to split hydrogen and oxygen in water, thereby producing hydrogen energy in a clean way, leaving virtually no pollutants. The technology, which was designed to simulate the natural energy-generating process of photosynthesis used by plants, was first successfully developed by American chemist Daniel G. Nocera and colleagues in 2011. Further work was needed to improve its efficiency and cost-effectiveness for practical use.

Humans are always interesting to know how does plant makes energy and we could copy plant because they do a great job creating energy from the bare minimum elements.

Plants take water from the environment and observe co2 from atmosphere and add an energy boost of sunlight and made glucose or sugar that they used energy and most oxygen and leftover water

6CO2 + 6H2O → C6H12O6 + 6O2 + 6H2O

(Carbon dioxide) (Water) (Glucose) (Oxygen) (Water)

But, instead of producing that glucose artificial leaf produces fuel that we humans can use the idea behind this technology is to produce cleaner-burning fuel while also scrubbing co2 from the air and producing oxygen now it no wonder that scientist have been trying to create one since, The 70s but, there is also a really good reason why they haven’t quite managed to make a fully functional commercial one yet now

There are many parts of photosynthesis that are really hard to do if you are not a plant one is that you need a catalyst that interacts with light energy to split water into hydrogen and oxygen.

A process called photolysis plants do this in their chloroplast ( the little energy-producing factory in the cell )

Some scientists have pursued creating systems that take light energy and make hydrogen which can further use as fuel this won’t work not just because it is a very complex process but, we don’t actually use hydrogen as fuel.

So scientists have to come up with a new idea to use this hydrogen and co2 from air to form an alternative fuel that something we humans can use as fuel now. Such as methanol scientists still finding a way to make it efficient and scale-able.

First Room-Temperature Superconductor Excites and Baffles Scientists

2020-11-26T09:33:00.002+05:30

Scientists have created a mystery material that seems to conduct electricity without any resistance at temperatures of up to about 15 °C. That’s a new record for superconductivity, a phenomenon usually associated with very cold temperatures. The material itself is poorly understood, but it shows the potential of a class of superconductors discovered in 2015.

The superconductor has one serious limitation, however: it survives only under extremely high pressures, approaching those at the centre of Earth, meaning that it will not have any immediate practical applications. Still, physicists hope it could pave the way for the development of zero-resistance materials that can function at lower pressures.

superconductors have a number of technological applications, from magnetic resonance imaging machines to mobile-phone towers, and researchers are beginning to experiment with them in high-performance generators for wind turbines. But their usefulness is still limited by the need for bulky cryogenics. Common superconductors work at atmospheric pressures, but only if they are kept very cold. Even the most sophisticated ones—copper oxide-based ceramic materials—work only below 133 kelvin (−140 °C). Superconductors that work at room temperature could have a big technological impact, for example in electronics that run faster without overheating.

The latest study, published in Nature on 14 October, seems to provide convincing evidence of high-temperature conductivity, says physicist Mikhail Eremets at the Max Planck Institute for Chemistry in Mainz, Germany—although he adds that he would like to see more “raw data” from the experiment. He adds that it vindicates a line of work that he started in 2015, when his group reported the first high-pressure, high-temperature superconductor—a compound of hydrogen and sulfur that had zero resistance up to −70 °C.

In 2018, a high-pressure compound of hydrogen and lanthanum was shown to be superconductive at −13 °C. But the latest result marks the first time this kind of superconductivity has been seen in a compound of three elements rather than two—the material is made of carbon, sulfur and hydrogen. Adding a third element greatly broadens the combinations that can be included in future experiments searching for new superconductors, says study co-author Ashkan Salamat, a physicist at the University of Nevada, Las Vegas. “We’ve opened a whole new region” of exploration, he says.

Materials that superconduct at high but not extreme pressures could already be put to use, says Maddury Somayazulu, a high-pressure-materials scientist at Argonne National Laboratory in Lemont, Illinois. The study shows that by “judiciously choosing the third and fourth element” in a superconductor, he says, you could in principle bring down its operational pressure.

The work also validates decades-old predictions by theoretical physicist Neil Ashcroft at Cornell University in Ithaca, New York, that hydrogen-rich materials might superconduct at temperatures much higher than was thought possible. “I think there were very few people outside of the high pressure community who took him seriously,” Somayazulu says.

MYSTERY MATERIAL

Physicist Ranga Dias at the University of Rochester in New York, along with Salamat and other collaborators, placed a mixture of carbon, hydrogen and sulfur in a microscopic niche they had carved between the tips of two diamonds. They then triggered chemical reactions in the sample with laser light, and watched as a crystal formed. As they lowered the experimental temperature, resistance to a current passed through the material dropped to zero, indicating that the sample had become superconductive. Then they increased the pressure, and found that this transition occurred at higher and higher temperatures. Their best result was a transition temperature of 287.7 kelvin at 267 gigapascals—2.6 million times atmospheric pressure at sea level.

he researchers also found some evidence that the crystal expelled its magnetic field at the transition temperature, a crucial test of superconductivity. But much about the material remains unknown, researchers warn. “There are a lot of things to do,” says Eremets. Even the crystal’s exact structure and chemical formula are not yet understood. “As you go to higher pressures, the sample size gets smaller,” says Salamat. “That’s what makes these types of measurements really challenging.”

High-pressure superconductors made of hydrogen and one other element are well understood. And researchers have made computer simulations of high-pressure mixtures of carbon, hydrogen and sulfur, says Eva Zurek, a computational chemist at the State University of New York at Buffalo. But she says those studies cannot explain the exceptionally high superconducting temperatures seen by Dias’s group. “I am sure, after this manuscript is published, many theoretical and experimental groups will jump on this problem,” she says.

BLOOD COGULATION

2020-11-23T15:30:00.004+05:30

Why blood clots ?

A blood clot is a clump of blood that has changed from a liquid to a gel-like or semisolid state. Clotting is a necessary process that can prevent you from losing too much blood in certain instances, such as when you’re injured or cut.

When a clot forms inside one of your veins, it won’t always dissolve on its own. This can be a very dangerous and even life-threatening situation.

An immobile blood clot generally won’t harm you, but there’s a chance that it could move and become dangerous. If a blood clot breaks free and travels through your veins to your heart and lungs, it can get stuck and prevent blood flow. This is a medical emergency.

You should call your doctor immediately if you think you might have a blood clot. A healthcare professional will be able to look at your symptoms and medical history and let you know what steps to take from there.

Mechanism of blood clothing

To stop bleeding, the body relies on the interaction of three processes:
Primary hemostasis involves the first two processes.
1. Vasoconstriction. Vasoconstriction is the body's first response to injury in the vascular wall. When injury occurs, vessel walls constrict, causing reduced blood flow to the site of injury.
2. platelets plug. Platelets aggregate to the site of the injury. They stick together acting as a "plug." Platelets also activate the process which causes a fibrin clot to form, known as secondary hemostasis.
Secondary hemostasis.
3. Platelets alone are not enough to secure the damage in the vessel wall. A clot must form at the site of injury. The formation of a clot depends upon several substances called clotting factors. These factors are designated by roman numerals I through XIII. These factors activate each other in what as known as the clotting cascade. The end result of this cascade is that fibrinogen, a soluble plasma protein, is cleaved into fibrin, a nonsoluble plasma protein. The fibrin proteins stick together forming a clot.
The clotting cascade occurs through two separate pathways that interact, the intrinsic and the extrinsic pathway.

Extrinsic Pathway
The extrinsic pathway is activated by external trauma that causes blood to escape from the vascular system. This pathway is quicker than the intrinsic pathway. It involves factor VII.

Intrinsic Pathway
The intrinsic pathway is activated by trauma inside the vascular system, and is activated by platelets, exposed endothelium, chemicals, or collagen. This pathway is slower than the extrinsic pathway, but more important. It involves factors XII, XI, IX, VIII.

Common Pathway
Both pathways meet and finish the pathway of clot production in what is known as the common pathway. The common pathway involves factors I, II, V, and X.

Disorder of blood clotting

Normal coagulation is important during an injury, as it helps stop a cut from bleeding and starts the healing process.

However, the blood shouldn’t clot when it’s just moving through the body. If blood tends to clot too much, it is referred to as a hypercoagulable state or thrombophilia.

Are hypercoagulable states dangerous?

Hypercoagulable states can be dangerous, especially when these conditions are not properly identified and treated. People with hypercoagulable states have an increased risk for blood clots developing in the arteries (blood vessels that carry blood away from the heart) and veins (blood vessels that carry blood to the heart). A clot inside a blood vessel is also called a thrombus or an embolus.

Blood clots in the veins or venous system can travel through the bloodstream and cause deep vein thrombosis (a blood clot in the veins of the pelvis, leg, arm, liver, intestines or kidneys) or a pulmonary embolus (blood clot in the lungs).

Blood clots in the arteries can increase the risk for stroke, heart attack, severe leg pain, difficulty walking, or even the loss of a limb.

What causes hypercoagulable states?

Hypercoagulable states are usually genetic (inherited) or acquired conditions. The genetic form of this disorder means a person is born with the tendency to form blood clots. Acquired conditions are usually a result of surgery, trauma, medications or a medical condition that increases the risk of hypercoagulable states.

Inherited hypercoagulable conditions include:

· Factor V Leiden (the most common)

· Prothrombin gene mutation

· Deficiencies of natural proteins that prevent clotting (such as antithrombin, protein C and protein S)

· Elevated levels of homocysteine

· Elevated levels of fibrinogen or dysfunctional fibrinogen (dysfibrinogenemia)

· Elevated levels of factor VIII (still being investigated as an inherited condition) and other factors including factor IX and XI

· Abnormal fibrinolytic system, including hypoplasminogenemia, dysplasminogenemia and elevation in levels of plasminogen activator inhibitor (PAI-1 )

Acquired hypercoagulable conditions include:

· Cancer

· Some medications used to treat cancer, such as tamoxifen, bevacizumab, thalidomide and lenalidomide

· Recent trauma or surgery

· Central venous catheter placement

· Obesity

Food that help in blood clotting

. Turmeric

People have long used the golden spice known as turmeric for culinary and medicinal purposes. The active ingredient in turmeric is curcumin that has anti-inflammatory and blood-thinning or anticoagulant properties.

A study published in 2012 suggests that taking a daily dose of turmeric spice may help people maintain the anticoagulant status of their blood.

People can add turmeric to curries and soups or mix it with hot water to make a comforting tea.

2. Ginger

Ginger is another anti-inflammatory spice that may stop blood clotting. It contains a natural acid called salicylate. Aspirin (acetylsalicylic acid) is a synthetic derivative of salicylate and a potent blood thinner.

To get the anticoagulant effects of natural salicylates, people may want to use fresh or dried ginger regularly in baking, cooking, and juices.

It is unlikely, however, that natural salicylates are as effective as blood-thinning medications.

A 2015 analysis of 10 studies also suggests that ginger’s effects on blood clotting are unclear. It indicates that more research is needed to understand the potential blood-thinning properties of ginger fully.

3. Cayenne peppers

Cayenne peppers are also high in salicylates and can act as powerful blood-thinning agents.

Cayenne pepper is quite spicy, however, and many people can only tolerate it in small amounts.

Capsules containing cayenne pepper are available in health food stores and online. Other benefits of this spice include lowering blood pressure, increasing circulation, and reducing pain sensations.

4. Vitamin E

Vitamin E reduces blood clotting in a few different ways. These effects depend on the amount of vitamin E that a person takes. The National Institutes of Health’s Office of Dietary Supplements suggest that people who are taking blood-thinning drugs should avoid taking large doses of vitamin E.

It is unclear how much vitamin E thins the blood, although it is likely that people would need to take more than 400 International Units (IU) per day. Taking high doses of vitamin E supplements, for example, above 1,500 IU daily, on a long-term basis, may have negative effects.

It may be safer to get vitamin E from foods rather than supplements. Foods that contain vitamin E include:

· almonds

· safflower oil

· sunflower oil

· sunflower seeds

· wheat germ oil

· whole grains

5. Garlic

Besides its often desirable taste in food and cooking, garlic has natural antibiotic and antimicrobial properties.

Some research reports that odorless garlic powder demonstrates antithrombotic activities. An antithrombotic agent is a substance that reduces blood clot formation.

Another review of several studies on garlic suggests that it may thin the blood, although the effects are small and short-lived.

The American Academy of Family Physicians nonetheless recommend that people stop taking high doses of garlic 7 to 10 days before a planned surgery because of its antithrombotic properties.

6. Cassia cinnamon

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HISTORY OF BIOLOGY DEVELOPMENT AS A SCIENCE

2020-11-18T19:13:00.001+05:30

Although the concept of biology as a special natural science originated in the XIX century, biological branches originated earlier in medicine and natural history. Usually, the main aspects of biology are formed by such ancient scholars as Aristotle and Galen through the Arab physicians Al-Jahiz, ibn-Sina, Ibn Zuhr and Ibn al-Nafis. During the Renaissance era, biological ideas in Europe have actualized thanks to the invention of typography and the spread of printed works, interest in experimental research and the discovery of many new species of animals and plants in the era of great geographical discoveries.

At that time, outstanding minds Andrei Vesalius and William Garvey worked, who laid the foundations of modern anatomy and physiology. Somewhat later, Linnaeus and Buffon did a great job of classifying the forms of living and fossil creatures. Microscopy has opened up the prior unspecified world of microorganisms for observation, laying the foundation for the cell theory development. The development of science, partly due to the emergence of a mechanistic philosophy, contributed to the development of natural history.

By the beginning of the XIX century, some modern biological branches, such as botany and zoology, had reached the professional level. Lavoisier and other chemists and physicists began a rapprochement of the concepts of animate and inanimate nature. Naturalists, such as Alexander von Humboldt, discovered the interaction of organisms with the surrounding and its dependence on geography, underlining the establishments of biogeography, ecology and ethology.

In the 19th century, the development of evolution theory gradually led to an understanding of the role of extinction and species variability, and cell theory showed in a new light the basis of the structure of living matter. In combination with the data of embryology and paleontology, these achievements have allowed Charles Darwin to create a holistic theory of evolution by natural selection. The end of the XIX century saw the ideas of abiogenesis finally which gave way to the theory of the infectious agent as the causative diseases’ agent. But the mechanism of inheritance of parental signs still remained a mystery.

At the beginning of the 20th century, Thomas Morgan and his students rediscovered the laws studied by Gregor Mendel in the middle of the 19th century, after which genetics began to develop rapidly. By the 1930s, a combination of population genetics and the theory of natural selection gave rise to modern evolutionary theory or neo-Darwinism. Due to the development of biochemistry, enzymes were discovered and a grandiose work began on the description of all metabolic processes. The disclosure of DNA structure by Watson and Crick gave a powerful impetus to the development of molecular biology. It was followed by the postulation of the central dogma, the deciphering of the genetic code, and by the end of the 20th century – and the complete deciphering of the human genetic code and several other organisms most important for medicine and agriculture.

Due to this, new disciplines of genomics and proteomics appeared. Although the increase in the number of disciplines and the extreme complexity of the subject of biology have given rise to and continue to give rise to an increasingly narrow specialization among biologists, biology continues to be a single science, and data from each of the biological branches, especially genomics, are applicable to all others.

EVERY ONE IS UNIQUE

2020-09-16T15:01:00.006+05:30

WHAT MAKE EVERY HUMAN UNIQUE

It’s often said that humans are 99.9% identical. and what makes us unique is a measly 0.1% of our genome. This may seem insignificant. But what these declarations fail to point out is that the human genome is made up of three billion base pairs—which means 0.1% is still equal to three million base pairs.

In those three million differences lie the changes that give you red hair instead of blonde, or green eyes instead of blue. You can find changes that increase your risk of obesity, or others that decrease your risk of heart disease; differences that make you taller or lactose intolerant, or allow you to run faster.

When I first started learning about genetic variation, I assumed these changes—the 0.1% that make us unique—only appeared in certain places, such as genes for height or inherited diseases like diabetes. I thought the rest of the genome—the other 99.9%—was fixed; that the 0.1% that was different in me was more or less the same 0.1% that was different in you. But, as it turns out, the 0.1% of DNA that is different between people is not always the same 0.1%: Variation can happen anywhere in our genomes.

In fact, one group of scientists looking at 10,000 people found variants at 146 million unique positions, or about 4.8% of the genome. Another group collected the DNA from 15,000 people and found 254 million variants, roughly 8% of the genome. And as we continue to sequence 100,000, 100 million, or all seven billion people on the planet, we will find a lot more variation. This means that humans have many more differences than we first thought.

Imagine that your DNA is a car. There are certain obvious variants you can have: blue or white, two-door or four-door, convertible or sedan. These changes represent the 0.1%. Because the other 99.9%—the engine, the seats, the steering wheel, the tires—has to be there for the car to work, we assume they are fixed.

But electric cars have shown us that we don’t need the gas cap, the gas tank, or even a gas engine any more; we can replace those things with a variant like batteries and charging ports. And maybe one day we’ll develop cars that have boosters instead of tires so we can hover over the ground.

In other words, what we believe is static may actually be variable. More than 0.1% of the car can change and it still be a car, just like the human genome.

WHAT IS QUANTUM PHYSICS

2020-09-15T20:00:00.006+05:30

WHAT IS QUANTUM PHYSICS

What is quantum physics? Put simply, it’s the physics that explains how everything works: the best description we have of the nature of the particles that make up matter and the forces with which they interact.

Quantum physics underlies how atoms work, and so why chemistry and biology work as they do. You, me and the gatepost – at some level at least, we’re all dancing to the quantum tune. If you want to explain how electrons move through a computer chip, how photons of light get turned to electrical current in a solar panel or amplify themselves in a laser, or even just how the sun keeps burning, you’ll need to use quantum physics.

But to understand how things work in the real world, quantum mechanics must be combined with other elements of physics – principally, Albert Einstein’s special theory of relativity, which explains what happens when things move very fast – to create what are known as quantum field theories.

Three different quantum field theories deal with three of the four fundamental forces by which matter interacts: electromagnetism, which explains how atoms hold together; the strong nuclear force, which explains the stability of the nucleus at the heart of the atom; and the weak nuclear force, which explains why some atoms undergo radioactive decay.

Over the past five decades or so these three theories have been brought together in a ramshackle coalition known as the “standard model” of particle physics. For all the impression that this model is slightly held together with sticky tape, it is the most accurately tested picture of matter’s basic working that’s ever been devised. Its crowning glory came in 2012 with the discovery of the Higgs boson, the particle that gives all other fundamental particles their mass, whose existence was predicted on the basis of quantum field theories as far back as 1964

Conventional quantum field theories work well in describing the results of experiments at high-energy particle smashers such as CERN’s Large Hadron Collider, where the Higgs was discovered, which probe matter at its smallest scales. But if you want to understand how things work in many less esoteric situations – how electrons move or don’t move through a solid material and so make a material a metal, an insulator or a semiconductor, for example – things get even more complex.

The billions upon billions of interactions in these crowded environments require the development of “effective field theories” that gloss over some of the gory details. The difficulty in constructing such theories is why many important questions in solid-state physics remain unresolved – for instance why at low temperatures some materials are superconductors that allow current without electrical resistance, and why we can’t get this trick to work at room temperature.

But beneath all these practical problems lies a huge quantum mystery. At a basic level, quantum physics predicts very strange things about how matter works that are completely at odds with how things seem to work in the real world. Quantum particles can behave like particles, located in a single place; or they can act like waves, distributed all over space or in several places at once. How they appear seems to depend on how we choose to measure them, and before we measure they seem to have no definite properties at all – leading us to a fundamental conundrum about the nature of basic reality.

This fuzziness leads to apparent paradoxes such as Schrödinger’s cat, in which thanks to an uncertain quantum process a cat is left dead and alive at the same time. But that’s not all. Quantum particles also seem to be able to affect each other instantaneously even when they are far away from each other. This truly bamboozling phenomenon is known as entanglement, or, in a phrase coined by Einstein (a great critic of quantum theory), “spooky action at a distance”. Such quantum powers are completely foreign to us, yet are the basis of emerging technologies such as ultra-secure quantum cryptography and ultra-powerful quantum computing.

Meanwhile cosmological measurements indicate that over 95 per cent of the universe consists of dark matter and dark energy, stuffs for which we currently have no explanation within the standard model, and conundrums such as the extent of the role of quantum physics in the messy workings of life remain unexplained. The world is at some level quantum – but whether quantum physics is the last word about the world remains an open question.

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