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Showing posts from July, 2022

What is depressions?

  Depression is the leading cause of disability in the world. In the United States, close to 10% of adults struggle with depression. But because it's a mental illness, it can be a lot harder to understand than, say, high cholesterol.  One major source of confusion is the difference between having depression and just feeling depressed. Almost everyone feels down from time to time getting a bad grade, losing a job, having an argument even a rainy day can bring on feelings of sadness. Sometimes there's no trigger at all, it just pops up out of the blue. Then circumstances change and those sad feelings disappear. Clinical depression is different. It's a medical disorder, and it won't go away just because you want it to. It lingers for at least two consecutive weeks and significantly interferes with one's ability to work play or love.  Depression can have a lot of different symptoms. A low mood loss of interest in things you'd normally enjoy, changes in appetite, fee...

How does laser eye surgery work ?

In 1948, Spanish ophthalmologist Jose Ignacio Barraquer Moner was fed up with glasses. He wanted a solution for the blurry vision that fixed the eye itself without relying on external aids, but the surgery he eventually devised was not for the faint of heart. Barraquer began by slicing off the front of a patient. Cornea and dunking it in liquid nitrogen. Using a miniature lathe, he grounded the frozen cornea into the precise shape necessary to focus the patient's vision. Then he thawed the disk and sewed it back on. Barraquer called this procedure Keratoma Eleusis from the Greek words for carving and cornea. And though it might sound grizzly, his technique produced reliable results. So how did barraquer surgery work? Keratoma hallucis corrects what are called refractive errors. Imperfections in the way the eye focuses incoming light, ideally the cornea and lens work together to focus light on the surface of the retina, but several kinds of refractive errors can impair this delicate...

How to get a word added to the dictionary ?

Dictionary noun a malevolent literary device for cramping. The growth of a language and making it hard and inelastic. Lexicographer noun a writer of dictionaries a harmless drudge. While the concept of a dictionary dates back to ancient civilizations. The first English Dictionary was published by Robert. Caudry in 1604. In the centuries that followed, many more dictionaries were written by individual authors who chose what to include or exclude. They not only defined words, they openly showcased their creators opinions like Ambrose Bierce's definition of dictionary and Samuel Johnson's definition of lexicographer. After their authors deaths, many of these dictionaries quickly became outdated but one. 19th Century Dictionary had a different fate. In 1828, American lawyer and author Noah Webster published an American Dictionary of the English language with a lofty goal to give the United States its own version of the English language. He believed that as a new nation, the United ...

How do self driving cars see?

  It's late pitch dark and a self driving car. Winds down a narrow country Rd. Suddenly 3 hazards appear at the same time. What happens next before it can navigate this onslaught of obstacles? The car has to detect them gleaning enough information about their size, shape and position so that its control algorithms can plot the safest course.  With no human at the wheel, the car needs smart eyes sensors that will resolve these details no matter the environment. Whether or how dark it is, all in a split second. That's a tall order, but there's a solution that partners two things, a special kind of laser based probe called LIDAR, and a miniature version of the communications technology that keeps the Internet humming called integrated photonics.  To understand Lidar, it helps to start with the related technology radar. In aviation radar antennas launch pulses of radio or microwaves at planes to learn their locations by timing how long the beams take to bounce back. That's ...

What if every satellite suddenly disappeared?

  One day without warning or apparent cause, all of humanity's artificial satellites suddenly disappear. The first to understand the situation are a handful of government and commercial operators, but well before they have time to process what's happened. Millions sitting on their couches become aware that something is amiss, TV that's broadcast from Or routed through satellites, dominate the market for international programming as well as some local channels. So the disappearance causes immediate disruptions worldwide.  The next people affected are those traveling by air, sea or land as global positioning, navigation and timing services have entirely ceased. Pilots, captains and drivers have to determine their locations using analog instruments and maps, aircraft ships and ground vehicles get stopped, grounded or returned to port. In the meantime, air traffic controllers have a difficult task on their hands to prevent plane crashes within.  Hours, most of the planet's ...

How does artificial intelligence learn ?

  Today, artificial intelligence helps doctors diagnose patients. Pilots fly commercial aircraft and city planners predict traffic, but no matter what these AI's are doing, the computer scientists who designed them likely don't know exactly how they're doing it. This is because artificial intelligence is often self-taught.  Working off a simple set of instructions to create a unique array of rules and strategies. So how exactly does a machine learn?  There are many different ways to build self teaching programs, but they all rely on the three basic types of machine learning, unsupervised learning, supervised learning and reinforcement learning to see these in action. Let's imagine researchers are trying to pull information from a set of medical data containing thousands of patient profiles.  First up, unsupervised learning, this approach would be ideal for analyzing all the profiles to find general similarities and useful patterns. Maybe certain patients have similar...

How do ultrasounds work ?

  In a pitch black cave, bats can't see much, but even with their eyes shut they can navigate rocky topography at incredible speeds. This is because of bats flight isn't just guided by its eyes, but rather by its ears. It may seem impossible to see with sound, but bats, naval officers and doctors do it all the time using the unique.  Properties of ultrasound all sound is created when molecules in the air, water or any other medium vibrate in a pulsing wave. The distance between each peak determines the waves frequency, measured as cycles per second or Hertz. This means that over the same amount of time, a high frequency wave will complete more cycles than a low frequency one. This is especially true of ultrasound, which includes any sound wave.  Exceeding 20,000 cycles per second. Humans can't hear or produce sounds with such high frequencies, but our flying friend can when it's too dark to see, he emits an ultrasound wave with tall peaks. Since the wave cycles are happ...

Using radioactive drugs to see inside your body ?

  This syringe contains a radioactive form of glucose, known as FDG. The Doctor will soon inject its contents into her patient's arm, whom she's testing for cancer using a pet scanner, the FDG will quickly circulate through his body if he has a tumor. Cancer cells within it will take up a significant portion of the FDG.  Which will act as a beacon for the scanner. PET tracers, such as FDG, are among the most remarkable tools in medical diagnostics and their life begins in a particle accelerator just hours earlier.  The particle accelerator in question is called a cyclotron and it's often housed in a bunker within hospitals. It uses electromagnetic fields to propel charged particles like protons, faster and faster along a spiraling path. When the protons reach their maximum speed, they shoot out onto a target that contains a few milliliters of a type of water with a heavy form of oxygen called oxygen 18. When a proton slams into one of these heavier oxygen.  Atoms, it...

How ocean work currently?

  In 1992, a cargo ship carrying Bath Toys got caught in a storm shipping containers washed overboard and the waves swept 28,000 rubber ducks and other toys into the North Pacific, but they didn't stick together. Quite the opposite, the Ducks have since washed up all over the world and researchers have used their paths to chart.  A better understanding of ocean currents. Ocean currents are driven by a range of sources. The wind tides changes in water density and the rotation of the earth.  The topography of the ocean floor and the shoreline modifies those motions, causing currents to speed up, slow down or change direction. Ocean currents fall into 2 main categories. Surface currents and deep ocean currents. Surface currents control the motion of the top 10% of the Ocean's water, while deep ocean currents mobilize the other 90%. Though they have different causes, surface and deep ocean currents influence each other. In an intricate dance that keeps the entire ocean moving...

What is the difference between scientific law and theory ?

  Chat with a friend about an established scientific theory and she might reply. Well, that's just a theory.  But a conversation about an established scientific law rarely ends with. Well, that's just a law. Why is that? What is the difference between a theory and a law? And is 1 better scientific laws and theories have different jobs? To do a scientific law predicts the results of certain initial conditions. It might predict your unborn child's possible hair colors, or how far a baseball travels when launched at a certain angle.  In contrast, a theory tries to provide the most logical explanation about why things happen as they do.  A theory might invoke dominant and recessive genes to explain how brown haired parents ended up with a redheaded child, or use gravity to shed light on the parabolic trajectory of a baseball. In simplest terms, a law predicts what happens while a theory proposes why.  A theory will never grow up into a law, though the development of...

How computer memory works ?

  In many ways, our memories make us who we are helping us remember our past, learn and retain skills and plan for the future and for the computers that often act as extensions of ourselves. Memory plays much the same role, whether it's a 2 hour movie, a two word text file, or the instructions for opening either everything in a computer's memory.  Takes the form of basic units called bits or binary digits. Each of these is stored in a memory cell that can switch between two states for two possible values, zero and one files, and programs consist of millions of these bits all processed in the central processing unit or CPU that acts as the computer's brain and as the number of bits needing to be processed grows exponentially. Computer designers.  Face a constant struggle between size, cost and speed. Like US computers have short term memory for immediate tasks and long term memory for more permanent storage. When you run a program, your operating system allocates area with...

Why do building fall in earthquakes?

  Earthquakes have always been a terrifying phenomenon and they've become more deadly as our cities have grown with collapsing buildings, posing one of the largest risks. Why do buildings collapse in an earthquake and how can it be prevented?  If you've watched a lot of disaster films, you might have the idea that building collapse is caused directly by the ground beneath them shaking violently, or even splitting apart, but that's not really how it works. For one thing, most buildings are not located right on a fault line and the shifting tectonic plates go much deeper than building foundations. So what's actually going on?  In fact, the reality of earthquakes and their effect on buildings is a bit more complicated to make sense of it. Architects and engineers use models like a two-dimensional array of lines representing columns and beams or a single line lollipop with circles representing the building's mass, even when simplified to this degree, these models can be...

How does your smartphone know your location ?

  How does your smartphone know exactly where you are? The answer lies 12,000 miles over your head in an orbiting satellite that keeps time to the beat of an atomic clock powered by quantum mechanics.  Foo let's break that down. First of all, why is it so important to know what time it is on a satellite when location is what we're concerned about? The first thing your phone needs to determine is how far it is from a satellite. Each satellite constantly broadcasts radio signals that travel from space to your phone at the speed of light. Your phone records the signal arrival time and uses it to calculate the distance to the satellite.  Using the simple formula, distance equals C times time. Where C is the speed of light and time is how long the signal traveled. But there's a problem. Light is incredibly fast. If we were only able to calculate time to the nearest second every location on Earth and far beyond would seem to be the same distance from the satellite. So in order ...

The life cycle of a plastic bottles?

  This is the story of three plastic bottles, empty and discarded. Their journeys are about to diverge with outcomes that impact nothing less than the fate of the planet.  But they weren't always this way to understand where these bottles end up, we must first explore their origins.  The heroes of our story were conceived in this oil refinery, the plastic in their bodies was formed by chemically bonding oil and gas molecules together to make monomers. In turn, these monomers were bonded into long polymer chains to make plastic in the form of millions of pellets. Those were melted at manufacturing plants and reformed in molds to create the resilient material that makes up the triplets, bodies, machines filled the bottles.  This sweet bubbly liquid and they were then wrapped, shipped, bought, opened, consumed and unceremoniously discarded and now here they lie poised at the edge of the unknown.  Bottle one like hundreds of millions of tons of his plastic brethren,...

How transistors work ?

  Modern computers are revolutionizing our lives, performing tasks unimaginable. Only decades ago, this was made possible by a long series of innovations, but there's one foundational invention that almost everything else relies upon the transistor. So what is that? And how does such a device enable all the amazing things computers can do?  Well, at their core all computers are just what the name implies. Machines that perform mathematical operations. The earliest computers were manual counting devices like the Abacus, while later ones used mechanical parts. What made them computers was having a way to represent numbers and a system for manipulating them. Electronic computers work the same way, but instead of physical arrangements the numbers are represented by electric voltages most such computers.  Is a type of math called Boolean Logic that has only two possible values, the logical conditions true and false, denoted by binary digits one and zero. They are represented b...

What is placebo effect? What is the power of the placebo effect ?

  In 1996, fifty six volunteers took part in a study to test a new painkiller called Trivero Ricaine. On each subject 1 index finger was covered in the new painkiller, while the other remained untouched. Then both were squeezed in painful clamps. The subjects reported that the treated finger hurt less than the untreated one. This shouldn't be surprising.  Except try Hurricane wasn't actually a painkiller, just a fake concoction with no pain easing properties at all.  What made the students so sure this dummy drug had worked? The answer lies in the placebo effect, an unexplained phenomenon wherein drugs, treatments and therapies that aren't supposed to have an effect and are often fake miraculously. Make people feel better. Doctors have used the term placebo since the 1700s when they realized the power of fake drugs to improve people's symptoms. These were administered when proper drugs weren't available, or if someone imagined they were ill.  In fact, the word place...

The surprising cause of stomach ulcers?

  In 1984, an enterprising Australian doctor named Barry Marshall decided to take a risk.  Too many of his patients were complaining of severe abdominal pain due to stomach ulcers, which are sores in the lining of the upper intestinal tract.  At the time, few effective treatments for ulcers existed and many sufferers required hospitalization or even surgery.  Desperate for answers, Doctor Marshall swallowed a cloudy broth of bacteria collected from the stomach of one of his patients.  Soon Doctor Marshall was experiencing the same abdominal pain, bloating and vomiting. 10 days later, a camera called an endoscope peered inside his insides. Marshall's stomach was teeming with the same bacteria as his patient. He'd also developed gastritis or severe inflammation of the stomach. The hallmark precursor of ulcers.  Doctor Marshall's idea challenged a misconception that still persists to this day that ulcers are caused by stress, food, or too much stomach acid Mar...

How to measure extremely distance? What is light seconds, light years, light centuries?

  Light is the fastest thing we know.  It's so fast that we measure enormous distances by how long it takes for light to travel them.  In one year, light travels about 6 trillion miles a distance we call one light year to give you an idea of just how far this is. The moon which took the Apollo astronauts 4 days to reach is only one light second from Earth.  Meanwhile, the nearest star beyond our own sun is Proxima Centauri 4.24 light years away. Our Milky Way is on the order of 100,000 light years across the nearest Galaxy to our own Andromeda is about 2.5 million light years away. Space is mind blowingly vast.  But wait, how do we know how far away stars and galaxies are? After all, when we look at the sky, we have a flat 2 dimensional view. If you point your finger to one star, you can't tell how far this star is. So how do astrophysicists figure that out?  For objects that are very close by, we can use a concept called trigonometric parallax. The idea is...

A brief history of electrical vehicles.

   If you were buying a car in 1899, you would have had three major options to choose from. You could buy a steam powered car, typically relying on gas powered boilers. These could drive as far as you wanted, provided you also wanted to lug around extra water to refuel and didn't mind waiting 30 minutes for your engine to heat up. Alternatively, you could buy a car  Powered by gasoline.  However, the internal combustion engines in these models require dangerous hand cranking to start and emitted loud noises and foul smelling exhaust while driving. So your best bet was probably option #3A battery powered electric vehicle. These cars were quick to start clean and quiet to run, and if you lived somewhere with access to electricity, easy to refuel overnight. If this seems like an easy choice, you're not alone by the end of the 19th century, nearly 40% of American cars were electric in cities with early electric systems. Battery powered cars were a popular.  And reli...

How do solar panel work ?

  The Earth intercepts a lot of solar power, 173,000 terawatts, that's 10,000 times more power than the planet's population uses. So is it possible that one day the world could be completely reliant on solar energy? To answer that question, we first need to examine how solar panels convert solar energy To electrical energy.  Solar panels are made-up of smaller units called solar cells. The most common solar cells are made from silicon, a semiconductor that is the second most abundant element on Earth in a solar cell, crystalline silicon is sandwiched between conductive layers. Each silicon atom is connected to its neighbors by 4 strong bonds, which keep the electrons in place so no current can flow. Here's the key. A silicon solar cell uses two different layers of silicon.  An N type silicon has extra electrons and P type silicon has extra spaces for electrons called holes, where the two types of silicon meet. Electrons can wander across the PN junction leaving a positive...

The origin of gold : How does gold come from ?

  In medieval times, alchemists tried to achieve the seemingly impossible. They wanted to transform lowly lead into gleaming gold. History portrays these people as aged eccentrics, but if only they'd known that their dreams were actually achievable. Indeed, today we can manufacture gold on Earth thanks to modern inventions.  That those medieval alchemists missed by a few centuries, but to understand how this precious metal became embedded in our planet to start with, we have to gaze upwards at the stars. Gold is extraterrestrial instead of arising from the planet's rocky crust. It was actually cooked up in space and is present on Earth because of cataclysmic stellar explosions called supernovae. Stars are mostly made-up of hydrogen, the simplest.  From lightest element, the enormous gravitational pressure of so much material compresses and triggers nuclear fusion in the stars core. This process releases energy from the hydrogen, making the star shine over many millions of...

The rise and fall of the Berlin wall ?

  In the early hours of August 13th, 1961, East German construction workers flanked by soldiers and police began tearing up streets and erecting barriers throughout the city of Berlin and its surroundings.  This night marked the beginning of one of history's most infamous dividing lines, the Berlin Wall. Construction on the wall continued for the next decade as it cut through neighborhoods, separated families and divided not just Germany but the world. To understand how we got to this point, we have to go back to World War Two, America, Britain and France joined forces with the Soviet Union against the Axis powers after they defeated Nazi Germany, each of the victorious nations occupied part of the country. The division was meant to be temporary, but the former allies found themselves at odds.  Over their visions for post war Europe, while Western powers promoted liberal market economies, the Soviet Union sought to surround itself with obedient communist nations, includin...

How do heart transplants work ?

  Your heart beats more than 100,000 times a day in just a minute, it pumps over 5 liters of blood throughout your body. But unlike skin and bones, the heart has a limited ability to repair itself. So if this organ is severely damaged, there's often only one medical solution replacing it.  Today, nearly 3500 heart transplants are performed each year in a complex and intricate procedure with no room for error. The process begins by testing potential recipients to ensure they're healthy enough for this demanding operation. Doctors are especially concerned with identifying immunocompromise.  Being illnesses or any other conditions that could compromise a patient's chance of survival. The next step is to match an eligible recipient with a heart donor.  Donors are often comatose patients with no chance of being resuscitated or victims of a fatal event whose hearts are still healthy. In both cases, these patients need to be registered as an organ donor or have their famili...