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If oil is more slippery than water, why is more dirt attracted to oily substances than water?
Viscosity of oil is high, so dirt is visible on surface. A lot of dirt dissolves in water, so it cannot be seen.
Viscosity of oil is high, so dirt is visible on surface. A lot of dirt dissolves in water, so it cannot be seen.
See lessWhen people want to remember something, why do they look at the sky?
Because we store information for later retrieval using one of three main sensory paths. People prefer one but use all three, visual, audio, and kinesthetic. To access memories, if a person prefers the visual “channel” they access the visual cortext and their eyes look up and to the left.
Because we store information for later retrieval using one of three main sensory paths. People prefer one but use all three, visual, audio, and kinesthetic. To access memories, if a person prefers the visual “channel” they access the visual cortext and their eyes look up and to the left.
See lessWhy do we feel uncomfort and nausea when eating rice in the morning?
Its main causes can be - (1) acidity or any other stomach disturbance, (2) blood sugar fluctuation, (3) allergies. Rice means carbohydrates, so the body may not adjust to eating rice suddenly in the morning. And eating more rice than other food is already a very bad diet plan, because of which manyRead more
Its main causes can be – (1) acidity or any other stomach disturbance, (2) blood sugar fluctuation, (3) allergies.
See lessRice means carbohydrates, so the body may not adjust to eating rice suddenly in the morning. And eating more rice than other food is already a very bad diet plan, because of which many Bengalis suffer from malnutrition. Instead you can have breakfast with milk, boiled egg and banana. Add a slice or two of bread if you want carbs. It should be eaten as a soup with almost no spices. If you can afford it, you can also eat frozen yogurt and lightly prepared chicken, along with seasonal fruits. And get up in the morning with a spoonful of honey with tulsi leaves, along with two pieces of amlaki.
Why is it not possible for mankind to develop from two people?
No, Humans Are Probably Not All Descended From A Single Couple Who Lived 200,000 Years Ago "All humans are descended from just TWO people and a catastrophic event almost wiped out ALL species 100,000 years ago, scientists claim". "Scientists Claim Humans Are Descended From Two People". "New ResearcRead more
No, Humans Are Probably Not All Descended From A Single Couple Who Lived 200,000 Years Ago
“All humans are descended from just TWO people and a catastrophic event almost wiped out ALL species 100,000 years ago, scientists claim”. “Scientists Claim Humans Are Descended From Two People”. “New Research Has Concluded That All Humans Are Descendants Of Just One Couple Who Lived 200,000 Years Ago”.
Those headlines give the impression that science has produced evidence to support the story of Adam and Eve. But the study they rest on does not demonstrate anything of the kind, and other lines of evidence strongly suggest that past human populations were always much larger than two.
The study in question was actually published in May and received coverage at the time, but has been picked up again. Its authors were Mark Stoeckle of Rockefeller University in New York and David Thaler of the University of Basel in Switzerland. It appeared in the journal Human Evolution, and it is “open access” so anyone can read it.
The study is about DNA barcoding: the technique of reading a small chunk of an organism’s DNA and using that to identify its species. To identify an animal, geneticists usually look at a gene called cytochrome oxidase 1 (CO1). This gene is not part of the “main” genome held in the nucleus of animal cells, but instead is carried in the mitochondria: tiny sausage-shaped organelles that swarm inside animal cells and provide them with energy.
DNA barcoding is not a perfect method of identifying species, but it works pretty well. That’s because, as the study observes, animals belonging to one species tend to have near-identical CO1 genes, which reliably differ from animals of other species.
Because CO1 genes are so similar within species, regardless of how many individuals there are, Stoeckle and Thaler argue that something must have made them that way. Either evolution is somehow pushing each species to have its own version, which seems unlikely, or each species has had almost all its genetic diversity purged – which implies that its population was once very small.
What’s more, these population bottlenecks seemingly all occurred between 100,000 and 200,000 years ago.
Much of the coverage has interpreted this as implying some sort of global event, an unspecified catastrophe that slashed the population of pretty much every animal species. However, Stoeckle and Thaler do not argue that, saying instead that species experience bottlenecks every few hundred thousand years due to the rough and tumble of life.
Thaler was quoted by Fox News saying that “all of animal life experiences pulses of growth and stasis or near extinction on similar time scales”. He listed possible explanations: “ice ages and other forms of environmental change, infections, predation, competition from other species and for limited resources, and interactions among these forces”.
The finding of a population bottleneck also applies to humans. The human genetic data, according to the study, is “consistent with the extreme bottleneck of a founding pair”.
The idea of humans being reduced to a population of two, who then had to repopulate the planet, has understandably drawn people’s attention. But this idea is almost certainly wrong, for a host of reasons.
First, we should always be hesitant about drawing big conclusions from mitochondrial DNA, and especially from a single gene – even if that gene has been examined in hundreds of species. Mitochondrial DNA is only inherited from one’s mother, so it necessarily only tells us about the female line. More importantly, because there is so little of it, it often misleads us. When the mitochondrial genome of Neanderthals was sequenced, it showed no sign that humans and Neanderthals had interbred. The interbreeding was only revealed when the Neanderthal nuclear genome was read.
Second, there is no trace in the geological record of any global event in the last 200,000 years. Any event that slashed populations that significantly would surely have led to a noticeable spike in the extinction rate, and there isn’t one. There are of course the extinctions linked to humans, but those occurred at separate times and locations, not simultaneously across the planet.
Indeed, the study’s finding that the event occurred between 100,000 and 200,000 years ago is too vague to imply a single event. It’s a bit like saying that the Napoleonic Wars happened after the fall of Mycenaean Greece but before 9/11. The suggested timespan is so vast, there is no reason to invoke a single event at all.
The whole pattern can be explained much more easily by saying that a lot of new species evolved over the last few hundred thousand years. That would not be surprising, because most species are indeed fairly young.
We don’t know for sure how long the average species lasts, partly because the fossil record is imperfect and partly because we don’t have a firm definition of what a species is anyway. But it’s been estimated that species typically last somewhere between 500,000 and 10 million years. It follows that a lot of species on Earth must have originated in the last few hundred thousand years. For instance, polar bears have been estimated to be about 400,000 years old as a species.
Stoeckle and Thaler’s findings would have us believe that 90 per cent of species are less than 200,000 years old. I don’t think their mitochondrial DNA data is enough to show that, and studies of whole genomes and fossils will give us more reliable dates that I would expect to be older. But they won’t be that much older. Given that the planet has been in and out of glacial periods over the last 2.5 million years, plus all the upheavals caused by humans and our extinct relatives, the finding that most species alive today are fairly young shouldn’t surprise us.
What about our own species? First, Stoeckle and Thaler only ever said that their data was “consistent” with the existence of a founding pair. That doesn’t mean much, and they immediately conceded that the same pattern could have arisen “within a founding population of thousands that was stable for tens of thousands of years”. The fact is, genomic data doesn’t do a great job of revealing the sizes of past populations except in broad-brush terms. The human population was probably pretty small for a long time, but there is no reason to think it was two.
Finally, the archaeological record tells a different story. It used to be thought that our species was about 200,000 years old, which would fit Stoeckle and Thaler’s data. However, in 2017 fossils uncovered at Jebel Irhoud in Morocco turned out to belong to our species, and they were around 300,000 years old. What’s more, our lineage split from that of the Neanderthals (our closest extinct relatives) roughly 500,000 years ago, so arguably our species is 500,000 years old. 200,000 years ago does not appear to have been a particularly special time in the history of our species.
Updated 22 December 2018: I have clarified that Stoeckle and Thaler do not propose a single catastrophic event simultaneously affecting large numbers of species.
This article is collected from: https://www.forbes.com/sites/michaelmarshalleurope/2018/11/26/no-humans-are-probably-not-all-descended-from-a-single-couple-who-lived-200000-years-ago/?
See lessWhy is antimatter so expensive?
The lower the supply of a product compared to the demand, the higher the price. Antimatter has not yet been proven 100% beyond doubt. So the price it shows is also very imaginary.
The lower the supply of a product compared to the demand, the higher the price.
See lessAntimatter has not yet been proven 100% beyond doubt. So the price it shows is also very imaginary.
Why are men’s testicles so sensitive, why is it so painful?
Being sensitive is because it is outside the body. Think about your other organs like stomach, uterus, bladder all but protected inside the body But the scrotum is surrounded by a thin membrane outside because sperm production requires a temperature lower than body temperature. Because it runs on aiRead more
Being sensitive is because it is outside the body. Think about your other organs like stomach, uterus, bladder all but protected inside the body But the scrotum is surrounded by a thin membrane outside because sperm production requires a temperature lower than body temperature. Because it runs on air cooled system. In winter you will see that the scrotum is closer to the body. And away from the body in hot weather. Now the question is why so sensitive. Because this thing is very important for human race. And if it was not sensitive, it would have been damaged in various ways. Everyone who is sensitive or feels a little pain, sits carefully or is in such a position that they do not feel pain and are ultimately protected.
See lessWhat are the types of systems in thermodynamics?
The system is three types- 1. Open system: These types of systems can exchange mass and energy with the environment. 2. Close system: These types of systems can exchange energy with the environment. But cannot exchange mass with the environment. 3. Isolated system: These types of systems cannot exchRead more
The system is three types-
See less1. Open system: These types of systems can exchange mass and energy with the environment.
2. Close system: These types of systems can exchange energy with the environment. But cannot exchange mass with the environment.
3. Isolated system: These types of systems cannot exchange both mass and energy with the environment.
What is the main motive of BRICS?
BRICS is an acronym for the powerful grouping of the world's leading emerging market economies, namely Brazil, Russia, India, China, and South Africa. The BRICS is motivated to promote peace, security, development, and cooperation.
BRICS is an acronym for the powerful grouping of the world’s leading emerging market economies, namely Brazil, Russia, India, China, and South Africa. The BRICS is motivated to promote peace, security, development, and cooperation.
See lessWhat was the total cost of Chandrayaan 3?
The cost of Chandrayaan-3 is only 615 crore rupees ($75 million US).
The cost of Chandrayaan-3 is only 615 crore rupees ($75 million US).
See lessWhy is the lunar mission or reaching the moon so important?
Reaching the moon means you have crossed the limits of the earth. It accumulates experience that gives courage to go to other planets later. There is also a political purpose to go to the moon, like the USA went to defeat Russia, China went to show its position, India went to show its capabilities.Read more
Reaching the moon means you have crossed the limits of the earth. It accumulates experience that gives courage to go to other planets later.
See lessThere is also a political purpose to go to the moon, like the USA went to defeat Russia, China went to show its position, India went to show its capabilities.
Going to the moon has long-term financial benefits. The first benefit is that it boosts the space agency’s reputation, thereby boosting their satellite business. Moreover, there are many mineral resources on the moon that an effort is underway to bring to earth, in this case those who are present will get the first share.
Through this last we will get to know many new things about our existence.
What is Kepler’s third law of gravitation?
Kepler’s third law is the law of the Time Period. It is- The line along the two circumferences of the ellipse is called the hypotenuse of the ellipse. Now if the planet is related to period.
Kepler’s third law is the law of the Time Period. It is-
See lessThe line along the two circumferences of the ellipse is called the hypotenuse of the ellipse. Now if the planet is related to period.
What is Kepler’s second law of gravitation?
Kepler’s second law is the law of area. It is- Consider that at any moment the planet is at one point and in 5 days it has moved to another point. Again at any moment, it was at one point, and in 5 days it moved to another point. The velocity of the planet will be such that, in both cases, the areaRead more
Kepler’s second law is the law of area. It is-
See lessConsider that at any moment the planet is at one point and in 5 days it has moved to another point. Again at any moment, it was at one point, and in 5 days it moved to another point. The velocity of the planet will be such that, in both cases, the area of the line connecting the planet and the sun is equal because the time was equal in this case. As you can see, when the planet is close to the sun, its velocity will be higher and when it is far away, its velocity will be lower.
Then the formula stands, “The radius connecting the planet and the sun will produce equal areas in equal time.
Now the question remains, then What will be the period of the planet? That is, how many days will be a year? The answer to this question can be found in Kepler’s third law. Which is known as the periodic formula.
What is Kepler’s first law of gravitation?
Kepler’s first law is the law of ellipses. It is- The Earth does not revolve around the sun in a circular but in an elliptical orbit. If we were talking about the circular path, we could safely say that the Sun is at the center of this circular orbit. But since the elliptical orbit has been talked aRead more
Kepler’s first law is the law of ellipses. It is-
See lessThe Earth does not revolve around the sun in a circular but in an elliptical orbit. If we were talking about the circular path, we could safely say that the Sun is at the center of this circular orbit. But since the elliptical orbit has been talked about, the question remains, Where is the sun in this ellipse? In response to such a question, Kepler pointed out, “The Earth moves in a definite elliptical orbit with the Sun at its focus.”
After the formula of elliptical orbit, the question remains, then What will be the velocity of the planet in this elliptical orbit? His second formula answers this question.
Why is India hesitant about BRICS?
This time India's attitude towards the BRICS summit has given rise to some controversy. There is a significant continuity in India's perception of this alliance. The idea is that the BRICS is an alliance of some of the world's revisionist forces, who do not want the destruction of the existing worldRead more
This time India’s attitude towards the BRICS summit has given rise to some controversy. There is a significant continuity in India’s perception of this alliance. The idea is that the BRICS is an alliance of some of the world’s revisionist forces, who do not want the destruction of the existing world order; Just want to include their interests in this system.
But time did not stop. Globalization has already gone haywire and the system of international institutions that underpins it is far from inclusive. While Russia and China are under US sanctions, on the other hand, India’s relationship with the US is perhaps at its highest in history. The two formed almost an alliance; Washington described it as the ‘most important partnership’ of the century. Not only that, it would not be wrong to say that the US sanctions against China are even benefiting India. A case in point is the ongoing closer ties between the two countries centered around the chip industry. Arguably, this could lead to a better quality of life in India. So there can be no reason for the country’s elites to be interested in a fundamental reconstruction of the existing international order, far from being destroyed.
The bottom line is that India will be satisfied if the world can be made a little more fair and stable by bridging the influence of BRICS. And this is not a pipe dream either. Because BRICS is on the right side of history. None of the members of this alliance have the reputation of using their existing economic opportunities and political influence, hard-earned and accumulated over centuries, to establish regional and global hegemony. As a result, India is feeling quite fluent in meeting its objectives.
It is in this context that prompts us to seek answers to the most fundamental question about BRICS – why countries like Indonesia, Iran, Egypt and Saudi Arabia are attracted to the alliance despite such divergent national characteristics, values and interests. These countries even believe that the alliance has the potential to take over the banner of global governance from the West. Of course, such expectations are unreasonable. Because they are based on a certain predetermined direction of evolution of the entire international system, which reality does not support. So it is only natural that Brazil or India may be concerned about how decisive the BRICS can truly become in world governance in the days to come. Frankly speaking, there is uncertainty about whether it is possible for the BRICS to maintain the revisionist behavior of the past in the current situation. The problem is not related to the outcome of the Ukraine conflict. Russia cannot and will not lose this war. However, it is unlikely that Russia’s adversaries will change their view of the world even if Go-Hara loses here.
Therefore, if BRICS expands without regard to norms, alliance unity may weaken and eventually the alliance may become loose and ineffective. This was the case with the Non-Aligned Movement. Yet it is time for transformation; To borrow WB Yeats’s wistful essay about the eternal principle of politics – that ‘the best men lack the least conviction, while the worst men are full of intensity of feeling.’
The situation is acute against the backdrop of the Ukraine conflict and the Biden administration’s dual blockade strategy against China and Russia, the two founding members of BRICS. Surprisingly, in the recent past, China and Russia have made dramatic changes in their worldviews and are strongly contesting US hegemony. The ‘borderless’ friendship between these two big neighbors has set them apart from other BRICS members. It can’t help but affect the chemistry of the alliance. Although their spirit of pragmatism and prudence continues, the spirit of unity continues. It should be noted that many countries want to join BRICS mainly from the idea that it supports a more equitable and less selfish world governance, especially with regard to small and medium-sized states. It can also be termed as a kind of second pillar of BRICS. Not to be forgotten, all the experience of powerful institutions and global governance is possessed by Western alliances built on common values and shared interests. But ironically, it has stuck them in a ‘block mentality’. BRICS lacks coordination and the ability to set the global agenda, which the G-7 has done for decades. That is why a country like India always expects the BRICS as a group to do something to improve the existing world order instead of destroying it. India does not want globalization, collapse of global institutions and international law. Put differently, India prefers to create rules, norms and means of cooperation within the existing system, which make it possible to preserve its advantages and eliminate defects.
For India, this is not only a strategy, but also a strategy. India feels somewhat secure in the conventional rule-based system; It reinforces polycentricity in Asia. It is not right that India is under pressure to ally with the US; It could have been said earlier. But today’s India, especially the current leadership, is consciously expanding ties with the US, which it considers to be in its own national interest. This is the logical outcome of India’s policy on the course of politics since the 1990s and the ‘bipartisan consensus’ between the ruling party and the main opposition. Due to long practice it now seems irreversible.
A number of factors are involved and one of the main reasons, seemingly contradictory, is the unprecedented rise of China, India’s BRICS partner, which has raised concerns within the country. A partnership with the US is one of the few ways that India finds effective ways to address security issues. Nevertheless, India can and should believe that India’s BRICS partners are capable of pursuing an independent foreign policy based on national interests. There is no reason to doubt that India believes in the ultimate influence of BRICS in setting key global agenda items needed to make the world more equitable and stable.
MK Bhadrakumar: Former Indian diplomat and political analyst; Translated by Saifur Rahman Tapan from RT.com
See lessWhy two poles of the magnet?
Almost all of us are familiar with magnets in childhood. It was great fun to take the magnet out of the toy car. And the magnets that could be bought separately, I didn't want to keep them. When we grow up, we understand that the magnet is very strange! We know that a magnet has two poles. North andRead more
Almost all of us are familiar with magnets in childhood. It was great fun to take the magnet out of the toy car. And the magnets that could be bought separately, I didn’t want to keep them. When we grow up, we understand that the magnet is very strange!
We know that a magnet has two poles. North and South Pole. Attracts iron and other things. However, the north pole of one bar magnet attracts the south pole of another bar magnet. But when the north pole is brought near the north pole, both the magnets are thrown in both directions. The strange thing is that if you cut or break a bar magnet in half, none of its poles will move. Instead, there are two new magnets, each with two poles!
Growing up, we learned that magnets only point north-south. East-West cannot be reversed. This is because the center of the earth is a magnet! That’s why the north pole of Earth’s geomagnet attracts the south pole of our toy magnets. And the north pole of our magnet attracts the south pole of the geomagnet. Magnets work great for this feature. We now know that not only toy cars, but also real cars or refrigerators have magnets. Even important medical tests such as MRI are performed using this magnetic property.
National High Magnetic Field Laboratory in Florida, USA. The director of this laboratory is Greg Boebinger. He says, ‘Magnets are one of the mysteries of physics. People have been using these magnets for thousands of years. But scientists are still learning new information about it.
This magnet has so many properties, the two poles of which are at the root – how are these poles made? We know that conducting electricity through iron shows its magnetism. Again the south pole of our magnet is attracted to the north pole of the geomagnet. But what is this magnet thing? How are the poles formed?
The most basic answer to this question is that the material that the magnet is made of contains atoms of that material. And there are electrons inside the atom. The real magic is these electrons.
At the center of the atom is the positively charged nucleus. And it is surrounded by one or more negatively charged electrons. Each electron creates a tiny magnetic field for its charge. Scientists call this property of electrons spin. If the poles of several of these microscopic magnetic fields are in the same direction, then the material becomes a magnet.
So the electron spin theory is an abstract concept. The name is ‘spin’, which is Bengali for rotation – so many people think that electron spin means it rotates. Not really. In fact, when a charged object rotates, a magnetic field is created around it. Scientists have measured such magnetic fields around electrons. They call the property of creating this magnetic field ‘spin’. Because, reversing the direction of the spin also reverses the pole of the magnetic field.
Electrons are usually paired. As a result the spin of one cancels the opposite spin of the other. As a result, the total magnetization value of any atom becomes zero. But this does not happen in some materials like iron. Let’s talk about iron. In iron atoms, the electrons are arranged around the nucleus in such a way that there is an odd electron in each atom. As a result, a microscopic magnetic field is created in each iron atom. That is why there is a religion of iron magnets.
In non-magnetic materials, the magnetic fields of each atom point in different directions. Not in any particular direction. The results cancel each other out in most cases, so eventually the material no longer exhibits magnetism. However, they can be turned in the same direction by conducting electricity or under the influence of a magnetic field. Then magnetism is seen in them too.
Now let’s talk about an interesting topic. Scientists have been searching for ‘magnetic monopoles’ for a long time. It can be called a stone of physics. But no trace of it has been found yet. Strangely, electrons and protons are electrically monopoles—that is, uniformly charged. Either negative or positive. As electrons are only negative. But in the magnetism created by electrons and other elementary particles again both poles are seen. And since these are elementary particles, they cannot be broken down. Physicists have stopped here. They no longer know whether the existence of unipolar magnets is really possible. Magnetism is therefore still a mystery. We still don’t know how to solve the mystery.
See lessWant to know the benefits of honey?
Aids in digestion: The sugars it contains are easily digested. Because the dextrin in it directly enters the blood and acts immediately. Honey is particularly beneficial for Petroga people. Constipation: Honey contains vitamin B complex. It relieves diarrhea and constipation. A teaspoon of pure honeRead more
Aids in digestion: The sugars it contains are easily digested. Because the dextrin in it directly enters the blood and acts immediately. Honey is particularly beneficial for Petroga people.
Constipation: Honey contains vitamin B complex. It relieves diarrhea and constipation. A teaspoon of pure honey taken in the morning relieves constipation and acidity.
Anemia: Honey is very effective in anemia as it helps in the formation of hemoglobin in the blood. It contains high amounts of copper, iron and manganese. Honey plays a good role in disease prevention. Honey is very good for dry skin. Mixing one teaspoon of honey, one teaspoon of milk and one teaspoon of lemon juice and applying it on the face for 10 minutes gives a beautiful glow to the skin. Honey prevents new acne from forming.
See lessWhich country recognized Bangladesh first?
Bhutan
Bhutan
See lessWhy many people use octane instead of petrol in bikes?
What is known as octane in Bangladesh is a slightly higher grade of petrol. This higher grade petrol or octane is used to get better engine performance.
What is known as octane in Bangladesh is a slightly higher grade of petrol. This higher grade petrol or octane is used to get better engine performance.
See lessWhat is the perpetual motion machine of the first kind of thermodynamics ?
A machine that violates the first law of thermodynamics is known as a perpetual motion machine of the first kind (briefly written as PMM-I). It is defined as a machine that produces work energy without consuming an equivalent of energy from other sources. Such a machine, is impossible to obtain in aRead more
A machine that violates the first law of thermodynamics is known as a perpetual motion machine of the first kind (briefly written as PMM-I).
It is defined as a machine that produces work energy without consuming an equivalent of energy from other sources. Such a machine, is impossible to obtain in actual practice because no machine can produce energy of its own without consuming any other form of energy.
See lessWhat is path function of thermodynamics?
There are certain quantities which cannot be located on a graph by a point but are given by the area or so, on that graph. In that case, the area on the graph, pertaining to the particular process, is a function of the path of the process. Such quantities are called path functions.
There are certain quantities which cannot be located on a graph by a point but are given by the area or so, on that graph. In that case, the area on the graph, pertaining to the particular process, is a function of the path of the process. Such quantities are called path functions.
See less