🔴The myth of Pegasus and the chimera

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🔴The myth of Pegasus and the chimera

Shielded from the gorgon’s stone-cold gaze, Perseus crept through Medusa’s cave. When he reached her, he took a deep breath, and in one sudden movement, drew his sickle and brought it down on her neck. Medusa’s head rolled to the ground and from her neck sprung two children.
One of them was Chrysaor, a giant wielding a golden sword; The other was the magnificent, white, winged horse, Pegasus. He was swifter than any other steed, and with the stomp of his hooves, he could alter mountains and draw streams from dry rock. No bridle could contain him— until one fateful day.
Bellerophon, prince of the Greek city-state of Corinth, seemed to have it all. But his ambitions exceeded his earthly circumstances. What he truly wanted was to be a hero so great that the gods would welcome him on Mount Olympus. Bellerophon believed that Pegasus would be key in helping him reach such heights.
One night, he visited the temple of Athena, the goddess of war and wisdom, and prayed for the power to appease the mighty animal. When Bellerophon woke, he found a magical golden bridle, and sped to the fountain that Pegasus drank from. As soon as the horse bent towards the water, Bellerophon jumped on his back and slipped the bridle on. Finally, Pegasus was subdued. With this conquest, Bellerophon felt that he was on his way to becoming a legendary hero. He trained for battle day and night. But one training session went horribly wrong, and Bellerophon mortally injured his brother, Deliades.
Disgraced, he was exiled to Argos, where King Proetus purified him. Bellerophon was resolved to repair his reputation, but the Queen of Argos had her eye on him. And when Bellerophon rebuffed her advances, she accused him of trying to seduce her, further tarnishing his honor.
King Proetus soon devised a plan to exact revenge. He banished Bellerophon and Pegasus and sent them to the kingdom of Lycia, carrying a note to Iobates, Lycia’s king. But unbeknownst to Bellerophon, he was carrying a decree for his own death. Iobates considered how to dispose of the youth and picked just the right monster for the job: the fire-breathing lion-goat-dragon Chimera that had long been terrorizing his kingdom. Bellerophon— eager to achieve greatness— jumped at the challenge.
He mounted Pegasus, and the two shot into the sky. Swooping above the earth, they saw the Chimera surrounded by its charred victims. Soon, they too were facing its firepower. In a sequence of agile aerial acrobatics, Pegasus dodged every blast from the Chimera as Bellerophon launched his arrows. Finally, Pegasus closed in on the beast at just the right angle, and Bellerophon dealt it a deadly blow.
Iobates was incredulous. He was glad to be rid of the monster, but still needed to deal with Bellerophon. So, he set forth more challenges, putting Bellerophon up against fearsome warriors, highly skilled archers, and, ultimately, Lycia’s best soldiers. Every time, Pegasus’ power turned the tide in Bellerophon’s favor.
Finally, Iobates had no choice but to concede that Bellerophon was a true hero. He even offered him his daughter’s hand in marriage. But Bellerophon’s sights were set far beyond the land of mortals. He was certain he must now be entitled to a place on Mount Olympus. So, he jumped onto Pegasus and urged him higher and higher.
Zeus watched as Bellerophon, buoyed by hubris, neared his palace. To punish the youth, he released a single gadfly, which beelined towards Pegasus and bit into his flesh. This was as high as Bellerophon would ever get. As Pegasus flinched, he flung his rider into the air, and Bellerophon fell careening back to Earth.
Pegasus, on the other hand, ascended with Zeus’s blessing. The gods welcomed him into the halls of Mount Olympus and immortalized him in a constellation. There in the night sky, Pegasus can be seen soaring, unfettered and free.

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🔴🔴پکیج رایگان نکات کاربردی گرامر سطح مبتدی برای داوطلبین کلیه آزمونهای بین المللی سنجش زبان در لینک زیر
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🔴The danger of silence

#Social_Change #Poetry #Spoken_Word

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🔴The danger of silence

Dr. Martin Luther King, Jr., in a 1968 speech where he reflects upon the Civil Rights Movement, states, "In the end, we will remember not the words of our enemies but the silence of our friends."
As a teacher, I've internalized this message. Every day, all around us, we see the consequences of silence manifest themselves in the form of discrimination, violence, genocide and war. In the classroom, I challenge my students to explore the silences in their own lives through poetry. We work together to fill those spaces, to recognize them, to name them, to understand that they don't have to be sources of shame. In an effort to create a culture within my classroom where students feel safe sharing the intimacies of their own silences, I have four core principles posted on the board that sits in the front of my class, which every student signs at the beginning of the year: read critically, write consciously, speak clearly, tell your truth.
And I find myself thinking a lot about that last point, tell your truth. And I realized that if I was going to ask my students to speak up, I was going to have to tell my truth and be honest with them about the times where I failed to do so.
So I tell them that growing up, as a kid in a Catholic family in New Orleans, during Lent I was always taught that the most meaningful thing one could do was to give something up, sacrifice something you typically indulge in to prove to God you understand his sanctity. I've given up soda, McDonald's, French fries, French kisses, and everything in between. But one year, I gave up speaking. I figured the most valuable thing I could sacrifice was my own voice, but it was like I hadn't realized that I had given that up a long time ago. I spent so much of my life telling people the things they wanted to hear instead of the things they needed to, told myself I wasn't meant to be anyone's conscience because I still had to figure out being my own, so sometimes I just wouldn't say anything, appeasing ignorance with my silence, unaware that validation doesn't need words to endorse its existence. When Christian was beat up for being gay, I put my hands in my pocket and walked with my head down as if I didn't even notice. I couldn't use my locker for weeks because the bolt on the lock reminded me of the one I had put on my lips when the homeless man on the corner looked at me with eyes up merely searching for an affirmation that he was worth seeing. I was more concerned with touching the screen on my Apple than actually feeding him one. When the woman at the fundraising gala said "I'm so proud of you. It must be so hard teaching those poor, unintelligent kids," I bit my lip, because apparently we needed her money more than my students needed their dignity.
We spend so much time listening to the things people are saying that we rarely pay attention to the things they don't. Silence is the residue of fear. It is feeling your flaws gut-wrench guillotine your tongue. It is the air retreating from your chest because it doesn't feel safe in your lungs. Silence is Rwandan genocide. Silence is Katrina. It is what you hear when there aren't enough body bags left. It is the sound after the noose is already tied. It is charring. It is chains. It is privilege. It is pain. There is no time to pick your battles when your battles have already picked you.

I will not let silence wrap itself around my indecision. I will tell Christian that he is a lion, a sanctuary of bravery and brilliance. I will ask that homeless man what his name is and how his day was, because sometimes all people want to be is human. I will tell that woman that my students can talk about transcendentalism like their last name was Thoreau, and just because you watched one episode of "The Wire" doesn't mean you know anything about my kids. So this year, instead of giving something up, I will live every day as if there were a microphone tucked under my tongue, a stage on the underside of my inhibition. Because who has to have a soapbox when all you've ever needed is your voice?
Thank you.

#Social_Change #Poetry #Spoken_Word

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🔴معرفی آزمون تافل هوم ادیشن، نحوه برگزاری آزمون و ویژگی های آن در لینک زیر
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🔴انجام تست کوتاه سنجش گرامر از طریق لینک زیر

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🔴Can you solve the prisoner hat riddle?

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🔴Can you solve the prisoner hat riddle?

You and nine other individuals have been captured by super intelligent alien overlords. The aliens think humans look quite tasty, but their civilization forbids eating highly logical and cooperative beings. Unfortunately, they're not sure whether you qualify, so they decide to give you all a test. Through its universal translator, the alien guarding you tells you the following: You will be placed in a single-file line facing forward in size order so that each of you can see everyone lined up ahead of you. You will not be able to look behind you or step out of line. Each of you will have either a black or a white hat on your head assigned randomly, and I won't tell you how many of each color there are. When I say to begin, each of you must guess the color of your hat starting with the person in the back and moving up the line. And don't even try saying words other than black or white or signaling some other way, like intonation or volume; you'll all be eaten immediately. If at least nine of you guess correctly, you'll all be spared. You have five minutes to discuss and come up with a plan, and then I'll line you up, assign your hats, and we'll begin. Can you think of a strategy guaranteed to save everyone? Pause the video now to figure it out for yourself. Answer in: 3 Answer in: 2 Answer in: 1 The key is that the person at the back of the line who can see everyone else's hats can use the words "black" or "white" to communicate some coded information. So what meaning can be assigned to those words that will allow everyone else to deduce their hat colors? It can't be the total number of black or white hats. There are more than two possible values, but what does have two possible values is that number's parity, that is whether it's odd or even. So the solution is to agree that whoever goes first will, for example, say "black" if he sees an odd number of black hats and "white" if he sees an even number of black hats. Let's see how it would play out if the hats were distributed like this. The tallest captive sees three black hats in front of him, so he says "black," telling everyone else he sees an odd number of black hats. He gets his own hat color wrong, but that's okay since you're collectively allowed to have one wrong answer. Prisoner two also sees an odd number of black hats, so she knows hers is white, and answers correctly. Prisoner three sees an even number of black hats, so he knows that his must be one of the black hats the first two prisoners saw. Prisoner four hears that and knows that she should be looking for an even number of black hats since one was behind her. But she only sees one, so she deduces that her hat is also black. Prisoners five through nine are each looking for an odd number of black hats, which they see, so they figure out that their hats are white. Now it all comes down to you at the front of the line. If the ninth prisoner saw an odd number of black hats, that can only mean one thing. You'll find that this strategy works for any possible arrangement of the hats. The first prisoner has a 50% chance of giving a wrong answer about his own hat, but the parity information he conveys allows everyone else to guess theirs with absolute certainty. Each begins by expecting to see an odd or even number of hats of the specified color. If what they count doesn't match, that means their own hat is that color. And everytime this happens, the next person in line will switch the parity they expect to see. So that's it, you're free to go. It looks like these aliens will have to go hungry, or find some less logical organisms to abduct.

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🔴What does the world's largest machine do?

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🔴What does the world's largest machine do?

On February 7th, 1967, Homer Loutzenheuser flipped a switch in Nebraska and realized a dream more than five decades in the making. The power grids of the United States joined together, forming one interconnected machine stretching coast to coast. Today, the US power grid is the world's largest machine. It contains more than 7,300 electricity-generating plants, linked by some 11 million kilometers of powerlines, transformers and substations.
Power grids span Earth’s continents, transmitting electricity around the clock. They’re massive feats of engineering— but their functioning depends on a delicate balance. Their components must always work in unison, maintain a constant frequency throughout the grid, and match energy supply with demand. If there's too much electricity in the system, you get unsafe power spikes that can overheat and damage equipment. Too little electricity and you get blackouts.
So, to strike this balance, power grid operators monitor the grid from sophisticated control centers. They forecast energy demand and adjust which power plants are active, signaling them to turn their output up or down to precisely meet current demand.
By considering factors like the availability and cost of energy resources, grid operators create a “dispatch curve,” which maps out the order in which energy sources will be used. The grid defaults to using energy from the start of the curve first. Usually, the resources are ordered by price. Those at the start tend to be renewables because they have much lower production costs. Some grids, like those in Iceland and Costa Rica, run on more than 98% clean energy. But most dispatch curves contain more of a mix of carbon-free and carbon-emitting energy sources. This means that where your electricity is coming from— and how clean it is— varies throughout the day— as often as every few minutes.
Take the state of Kansas. Despite having plentiful wind resources, it regularly relies on carbon-emitting power plants. This is because wind energy is especially plentiful at night. But, this is also when there’s lower demand. So, Kansas’ is wind energy is actually regularly disposed of to prevent excess electricity from damaging the grid. And comparable scenarios add up to a big problem worldwide. Thankfully, dependence on renewables is rising. But power grids are often unable to make full use of them.
Many simply weren't designed around intermittent energy sources and can't store large amounts of electricity. Researchers are experimenting with unique storage solutions. However, this will take time and substantial investment. But hope is not lost. We have the opportunity to work with our existing power grids in a new way: by shifting some of our energy use to the times when there’s clean electricity to spare. Leaning into this concept, called “load flexibility,” we can help flatten the peaks in demand, which will place less stress on the grid and reduce the need for non-renewables.
So researchers are developing automated emissions reduction technologies that tap into energy use data and ensure that devices get electricity from the grid at the cleanest times. In fact, smart devices like this already exist. So, how big an effect could they have? If smart technologies like air conditioners, water heaters, and electric vehicle chargers were implemented across the Texas power grid, the state’s emissions could decrease by around 20%. In other words, simply coordinating when certain devices tap into the grid could translate to 6 million fewer tons of carbon released into the atmosphere annually from Texas alone. Now, imagine what this could look like on a global scale.

#Education #Energy #TED_Ed #Natural_Resources #Animation #Electricity #Renewable_Energy

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💥مجموعه ای از تست های رایگان تعیین سطح زبان ویژه متقاضیان آیلتس، تافل در کلیه سطوح تنها در ۲۰ دقیقه در بخش های گرامر، واژگان، ریدینگ و کالوکیشن در لینک زیر
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🔴The 4 greatest threats to the survival of humanity

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🔴The 4 greatest threats to the survival of humanity

In January of 1995, Russia detected a nuclear missile headed its way. The alert went all the way to the president, who was deciding whether to strike back when another system contradicted the initial warning. What they thought was the first missile in a massive attack was actually a research rocket studying the Northern Lights. This incident happened after the end of the Cold War, but was nevertheless one of the closest calls we’ve had to igniting a global nuclear war.
With the invention of the atomic bomb, humanity gained the power to destroy itself for the first time in our history. Since then, our existential risk— risk of either extinction or the unrecoverable collapse of human civilization— has steadily increased. It’s well within our power to reduce this risk, but in order to do so, we have to understand which of our activities pose existential threats now, and which might in the future.
So far, our species has survived 2,000 centuries, each with some extinction risk from natural causes— asteroid impacts, supervolcanoes, and the like. Assessing existential risk is an inherently uncertain business because usually when we try to figure out how likely something is, we check how often it's happened before. But the complete destruction of humanity has never happened before. While there’s no perfect method to determine our risk from natural threats, experts estimate it’s about 1 in 10,000 per century.
Nuclear weapons were our first addition to that baseline. While there are many risks associated with nuclear weapons, the existential risk comes from the possibility of a global nuclear war that leads to a nuclear winter, where soot from burning cities blocks out the sun for years, causing the crops that humanity depends on to fail. We haven't had a nuclear war yet, but our track record is too short to tell if they’re inherently unlikely or we’ve simply been lucky. We also can’t say for sure whether a global nuclear war would cause a nuclear winter so severe it would pose an existential threat to humanity.
The next major addition to our existential risk was climate change. Like nuclear war, climate change could result in a lot of terrible scenarios that we should be working hard to avoid, but that would stop short of causing extinction or unrecoverable collapse. We expect a few degrees Celsius of warming, but can’t yet completely rule out 6 or even 10 degrees, which would cause a calamity of possibly unprecedented proportions. Even in this worst-case scenario, it’s not clear whether warming would pose a direct existential risk, but the disruption it would cause would likely make us more vulnerable to other existential risks.
The greatest risks may come from technologies that are still emerging. Take engineered pandemics. The biggest catastrophes in human history have been from pandemics. And biotechnology is enabling us to modify and create germs that could be much more deadly than naturally occurring ones. Such germs could cause pandemics through biowarfare and research accidents. Decreased costs of genome sequencing and modification, along with increased availability of potentially dangerous information like the published genomes of deadly viruses, also increase the number of people and groups who could potentially create such pathogens.
Another concern is unaligned AI. Most AI researchers think this will be the century where we develop artificial intelligence that surpasses human abilities across the board. If we cede this advantage, we place our future in the hands of the systems we create. Even if created solely with humanity’s best interests in mind, superintelligent AI could pose an existential risk if it isn’t perfectly aligned with human values— a task scientists are finding extremely difficult.

Based on what we know at this point, some experts estimate the anthropogenic existential risk is more than 100 times higher than the background rate of natural risk. But these odds depend heavily on human choices. Because most of the risk is from human action, and it’s within human control. If we treat safeguarding humanity's future as the defining issue of our time, we can reduce this risk. Whether humanity fulfils its potential— or not— is in our hands.

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🔴Why is it so hard to cure the common cold?

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🔴Why is it so hard to cure the common cold?

In 2000, a company called ViroPharma ran clinical trials of pleconaril, a new pill designed to treat the common cold. In many patients, the pill helped. But in 7 of them, just a few days into the treatment, researchers found mutated virus variants that were almost completely resistant to pleconaril.
Viruses are always mutating, but this one mutated so quickly that it managed to outmaneuver years of research and development in just a few days.
If you didn't have an immune system and caught a cold, the infection would quickly spread deep into your lungs. Rampant viral replication would destroy tissue there, until your lungs couldn’t supply your body with enough oxygen and you’d asphyxiate.
Unfortunately, for millions of people around the world who live with a less-than-fully-functional immune system or who are on immunosuppressant drugs, this is a real risk: “minor” infections can turn serious or even deadly.
But if you're fortunate enough to have a fully functional immune system, a cold will probably give you a few relatively mild symptoms. On average, adults catch more than 150 colds throughout their lives. And despite the fact that the symptoms are similar, the cause could be different each time
Common colds are caused by at least 8 different families of virus, each of which can have its own species and subtypes.
How can so many different viruses cause the same illness? Well, viruses can only invade our bodies in a few ways: one is to come in on a breath. We have to breathe, so our immune system sets up a bunch of frontline defenses and these are actually what produce many of the symptoms of a cold. Your mucus-y, dripping nose is your immune system trapping and flushing out virus. Your fever is your immune system raising your body temperature to slow down viral replication. And your inflamed, well, everything, that’s your immune system widening your blood vessels and recruiting its white blood cell army to help kill the virus.
So, if the common cold is caused by many different viruses, is a cure even possible?
Here’s one fact in our favor: a single family of viruses causes 30 to 50% of all colds: rhinovirus. If we could eliminate all rhinovirus infections, we’d be a long way towards curing the common cold.
There are two main ways to fight a virus: vaccines and antiviral drugs.
The first attempt to create a rhinovirus vaccine was a success— but a short-lived one. In 1957, William Price vaccinated 50 kids with inactivated rhinovirus and gave 50 others a placebo. Soon afterwards, a rhinovirus outbreak spread throughout the kids. In the vaccinated group, only 3 got sick. In the placebo group, 23 did— almost 8 times as many. And despite the small numbers, this was promising: the immune systems of vaccinated kids were successfully recognizing and responding to rhinovirus.
But later trials of the vaccine showed no protection at all— none. This wasn’t Price’s fault— no one at the time knew that rhinovirus had multiple subtypes. Price’s vaccine, for reasons we don’t fully understand, didn't provide broad protection, meaning it was only effective against one or maybe a few subtypes of rhinovirus— out of 169 subtypes and counting.
Sometimes, when we make a vaccine, we get lucky. The mRNA COVID vaccines, for example, effectively protect us against severe disease and death across the original virus and variants too.
But we have yet to create a broadly protective vaccine against rhinovirus, or any other virus that causes the common cold.
Okay, what about antiviral drugs?
Viruses hijack human cellular machinery to replicate and spread, so it’s hard to make a molecule that’s toxic to the virus without also being toxic to the human. And even if you manage to do that, the virus could mutate out of reach of the drug.

Viruses are slippery beasts. We have, though, had some incredible successes: we eradicated smallpox thanks to an effective vaccine, the fact that it can’t hide out in other species, and its relatively low mutation rate. HIV, on the other hand, mutates so quickly that in an untreated individual, every possible single-letter mutation in the virus’s genetic code could, in theory, be produced in a single day.
Despite trying for decades, we still don’t have a vaccine. But we do have an effective cocktail of HIV drugs that the virus can’t easily mutate away from.
Unfortunately, we are stuck with colds for now. But the last few decades have featured some entirely game-changing medical breakthroughs, like mRNA vaccines and CRISPR. CRISPR could be particularly promising as an antiviral agent, because it originally evolved in bacteria as an immune defense against viruses. In fact, early in the COVID-19 pandemic, a research team showed that a CRISPR system could degrade coronavirus and influenza genomes in our lung cells. They called their system prophylactic antiviral CRISPR in human cells.

#Education #Disease #Health #Health_Care #Medicine #Illness #Vaccines #Virus #Medical_Research #TED_Ed #Animation #Human_Body #Coronavirus

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🔴تست رایگان تعیین سطح ریدینگ آیلتس با توجه به درخواست های متقاضیان در لینک زیر👇👇

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🔴What's the smartest age?

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