Thursday, March 29, 2012

What an anti-virus program does.

Let's pretend that your computer is a treehouse club that you like to play in and invite friends over to.

Anti-Virus is like a bouncer standing at the door of the club. Except this guy has a list of bad people who he looks out for and when they try to go into the club he stops them.
f there are new bad kids in the neighborhood that the bouncer doesn't know about he might let them in so it is important to make sure his list of bad people is kept up-to-date.

It is also important for you to avoid inviting random kids you meet in bad areas of town to come and play. Some places are known hangouts for trouble makers.

Norton Anti Virus is a big heavy slow bouncer who asks for money every year and he is clumsy and gets in the way a lot when you are trying to play in the treehouse.

Microsoft Security Essentials is a skinny fast martial arts expert who stays out of sight except when he is needed and has a good up-to-date list of bad kids all the time without asking you for any money.

There are other good free bouncers out there too. I happen to like Microsoft Security Essentials at the moment. A few years ago AVG Free was good but he has put on a few pounds and slowed down lately in my opinion.

I like to have Malwarebytes Anti Malware as well. He is a bouncer who is extra good at recognizing kids who try to come in and spy on you and pass the information on to their friends. He stops kids listening near the door for your secret passwords and any gossip about you and your friends.

Even the best bouncers cannot help you if you invite people and show them in yourself. Some bad kids pretend to be bouncers and trick you into letting them into the treehouse. Don't fall for this!

Why kids in school buses don't have to wear seat belts.

Despite the odd incident, school buses are really safe.

Like, really, really safe.

On average 11 children die / year in school bus accidents according to The Straight Dope and only 6 per year according to some article that's using the National Highway Traffic Safety Administration as a source. That's for 24 million children being transported more than 4.3 billion miles a year, according to that article.

That and kids just aren't good at wearing seat belts. They slouch, or sit sideways, or have their legs up and whatever else. All those things mean that the seat belts would probably be worse that not wearing one at all. Considering the weight of a bus and the fact that they're more likely to run through anything they hit, it's best if children don't actually wear seat belts.

So, the expense needed to install seat belts in school buses and the barely marginal increase in safety doesn't justify installing them.

Even so, California and Texas requires lap-shoulder belts on new buses and New York, New Jersey and Florida require lap belts.

Monday, November 14, 2011

Mexican Drug Cartel.

Pretend that you want to sell chocolate to everyone at school. You are making a lot of money because everyone is buying the chocolate from you. Then you find out someone else is selling chocolate too so you are not making that much money anymore. You have a choice to compete with them or just mess them up so they can't sell chocolate anymore.

The teachers find out you're selling chocolate so they make a rule that you can't sell chocolate. So you beat up the teacher and show everyone what you did to warn other teachers to not stop you from selling chocolate.

Chocolate is banned from the school so the principal can't regulate the sales of the chocolate and generate tax revenue from it so the school can buy new books. The principal is the one who banned them in the first place.

Chocolate = drugs
Teachers = police
Principal = the government

Thursday, October 27, 2011

Different types of air purifiers.

There are 3 main types of air purifiers: Electronic air cleaners, dehumidifiers, and ultra violet germicidal lights.

Electronic Air Cleaners - Most use electricity to make the particles in the air be negatively or positively charged. Than another part of it is the magnet which will grab the particle that was just charged. These usually do a great job of cleaning the air but they have to be maintained very well to keep up the effectness.

Dehumidifiers - This controls the humidity in your house. If you have high humidity in your home, it causes things to grow on the particles that you breathe. If you run an air conditioner and a dehumidifier at the same time, the dehumidifers will keep the inside of the air conditioner dry which prevents things from growing inside.

Ultra Violet Germicidal Lights - These are supposed to use a light that kills stuff in the air but there are mixed reviews on these. But the air is moving too fast for the light to do anything.

Why are tattoos permanent.

Tattoo Ink Placement

The tattooing process causes damage to the epidermis, epidermal-dermal junction, and the papillary layer (topmost layer) of the dermis. These layers appear homogenized (or in other words, like mush) right after the tattooing process. The ink itself is initially dispersed as fine granules in the upper dermis, but aggregate into more concentrated areas at 7-13 days.

Like any injury, the initial response is to stop bleeding, followed by tissue swelling, and the migration of non-resident immune cells into the area. The "automatic response" immune cells are mostly neutrophils, and macrophages later on. They are phagocytic cells that "swallow" debris to clean up the area and then leave via the lymphatics. This is the extent of an immune response unless an allergic reaction occurs or an infection sets in. The tissue is then repaired and/or regenerated by fibroblasts. Initially the tissue formed is known as granulation tissue (think fresh scar, pinkish and soft), which later matures into fibrous tissue (think old scar).

Stages of Ink Dispersal

Initially ink is taken up by keratinocytes, and phagocytic cells (including fibroblasts, macrophages and mast cells).

At one month the basement membrane of the epidermis (epidermal-dermal junction) is reforming and the basal cells contain ink. In the dermis, ink containing phagocytic cells are concentrated along the epidermal-dermal junction below a layer of granulation tissue that is surrounded by collagen. Ink is still being eliminated through the epidermis with ink present in keratinocytes, macrophages and fibroblasts.

At two to three months the basement membrane of the epidermis is fully reformed, preventing any further loss of ink through the epidermis. Ink is now present in dermal fibroblasts. Most of these ink containing fibroblasts are located beneath a layer of fibrous tissue which has replaced the granulation tissue. A network of connective tissue surrounds and effectively traps these fibroblasts. It is assumed that these fibroblasts are the cells that give tattoos their lifespan.

Then why does the tattoo fade over time?

It is debated whether all the ink particles are in fibroblasts, or if some remain as extracellular aggregations of ink. Also, the lifespan of the ink containing fibroblasts is not known. Presumably, ink particles are moved into the deeper dermis over time due to the action of mobile phagocytic cells (think immune cells), causing the tattoo to look bluish, faded and blurry. Examination of older tattoos (e.g. 40 years) show that the ink is in the deep dermis, and also found in local lymph nodes. Since some types of phagocytic immune cells migrate to lymph nodes to "present their goods", the discovery of ink in lymph nodes is consistent with the theory of phagocytic cells being the cause of ink movement.


Friday, October 21, 2011

Why Gaddafi was killed.

Gaddafi was the ruler of Libya. The people didn't vote him to be leader, he took over by intimidation. When he was the leader, he was very very mean to anyone who didn't want him to be the ruler. He even killed people who weren't on his side, like protesters! Also, as the ruler of Libya, Gaddafi was in control of the oil exported from the country and he made a lot of money selling it. However, he didn't share this large wealth with the people of Libya, even though many of them were very poor. All of these things made people very angry, and they wanted to make him pay for killing the protesters and keeping all the oil money for himself and his family, so they became violent and killed him.

Thursday, October 20, 2011

What happens when a country defaults on its debt.

Say you have a little country of your own, off on an island someplace. You and a few hundred friends, let's say it is. You have a government — monarchy, republic, whatever; doesn't matter. That government has a treasury, but the treasury has no money in it. Which is fine … so long as you don't actually want your government to do anything. If you just want to be able to say you have a government, knock yourself out; nobody can stop you. But as soon as you want that government to do stuff — like hiring police officers, or raising an army — you need money in your treasury.

The way this works is simple: Your treasury issues bonds. A bond is sort of like a very ritualized type of loan. You sell bonds with the promise to, after a set amount of time, buy them back for more than what you sold them for. So say you could sell a bond for $100, with the promise to buy it back in a year for $110. The difference between how much you promise to buy the bond back for and how much it sells for, expressed as a percentage, is called the interest, and the date on which you promise to buy it back is called the maturity.
Who buys bonds? Who cares? Literally anybody with money can buy these bonds. Maybe those are private citizens in your country, maybe it's your central bank (that's how you create money in your economy in the first place), or maybe it's private citizens or other concerns in other countries. Point is, you offer the bonds for sale, and people agree to buy them. Thus do you get money in your treasury.

Of course, people will only agree to buy your treasury's bonds if they think there's a good chance your treasury will buy them back when it promises to. If there's reason to doubt your treasury's willingness or ability to buy the bonds back, the people who have the money to buy them will demand a higher rate of interest to justify the higher risk.
If there's a lot of reason to doubt your treasury's willingness or ability to pay, potential bond buyers might demand an impossibly high interest rate, making it effectively impossible for you to sell bonds, which in turn means it's effectively impossible for you to fund your government's activities.

When one of those government activities you can no longer fund is redeeming previously issued bonds, you've got yourself a sovereign debt crisis. And when a debt crisis gets really bad, you've got yourself a sovereign default situation.

So your question is what happens in a sovereign default situation? Well, most of the time the answer is that doesn't come up, because people, on the whole, aren't complete idiots. You can see a sovereign default situation coming from a mile away. When confidence in your bonds drops, and the demand price rises as a result, it's clear that you're going to have a problem in the future if you don't take measures to prevent it. So people, as a rule, tend to have plenty of chances to see these things coming and avert them.

But sometimes that doesn't happen. (In the case of Greece, it didn't play out that way because there was a big disconnect between the perceived value of Greek sovereign bonds and their actual value, due to what we could charitably call reporting irregularities. When that disconnect was resolved, the market value of Greek sovereign bonds dropped like a rock practically overnight.) In those cases — where a sovereign default situation occurs anyway — one of two things can happen.

Most of the time, you end up with what's called a controlled default. This includes two parts: a restructuring of the sovereign debt, and a guarantor.
In the broadest terms, sovereign debt restructuring just means rearranging things to reduce the debt burden on the treasury in question. That might mean getting holders of bonds to agree to new terms of repayment, or it might mean somebody buying up a bunch of bonds on the open market and then destroying them, whatever. It's usually very complicated, but the general principle is that the country's sovereign debt obligation is changed to reduce the scope of the problem and increase the chance that the holders of those bonds will get at least some return on their investment.

A guarantor, on the other hand, is some body that injects capital into the treasury to cover bond repayments. In the modern era, that's usually the International Monetary Fund, or IMF. The IMF functions much like an insurance underwriter: Countries pay into the fund as they can, and in return receive the right to draw on the fund if needed. In a sovereign default situation, the IMF will extend loans to the troubled treasury — usually loans with lots of very short strings attached — to guarantee the treasury retains the ability to redeem its outstanding bonds as it recovers from its debt crisis. Having a guarantor is good, because it raises market confidence in your ability and willingness to buy back new bonds, meaning you can get money flowing through your treasury again, which is how you climb out of a debt crisis.

But remember I said that only happens — the thing with the restructuring and the guarantor — most of the time. It's also entirely possible for a government to just say "screw it, we ain't payin'." When that happens — and it's worth remembering that in the modern era it's exceedingly rare — the people who hold those bonds just take it in the shorts. The bonds become absolutely, literally worthless; you're better off burning them to heat your house than you are holding on to them in the hope of future repayment.

Of course, the failure of a government to buy back its bonds doesn't just render those bonds worthless. It renders all future bonds issued by the same treasury worthless. Because once a government exercises its power — and it is a power; nobody can stop it from happening — to nullify its bonds, what's to stop it from using that power again the next time a series of bonds matures? Nothing, is the answer. So once a government has demonstrated its willingness to say "screw you" to investors, faith in that government is ruined forever. Meaning that government can no longer fund its operations, meaning it can no longer do anything, meaning it no longer has any reason to exist, as far as its people are concerned. That's how you end up with things like the fall of the Weimar Republic … which is precisely why today we have this vast infrastructure in place to keep things from getting to that point.

Monday, October 17, 2011

How a silencer works.

When a gun fires a bullet, the bullet breaks the sound barrier and creates a sonic boom sound. A gun that fires a bullet which breaks the sound barrier is impossible to suppress without slowing down the bullet.

The way a gun fires a bullet is by creating enough pressure behind the bullet to push it out of the barrel. There are very hot gasses which expand very quickly. A suppressor (also known as a silencer) slows the expansion of the gas outside of the barrel. If you were to disassemble a suppressor, you would see it is basically a tube with small holes that feed into another chamber. By giving the gasses a slightly larger area to expand in, it allows the gas to expand and cool at a slower rate.

Friday, October 14, 2011

Photography terms.

Imagine a dark room with a window covered with blinds, the blinds are like a shutter, it opens up to let light in.

Shutter speed is how long the blinds stay open for. The longer the blinds stay open, the more light gets into the room. One of the reasons a picture can turn out blurry is if a person moves while the blinds are still open.

One of the things that determines how much light reaches the sensor in your camera is called aperture. The aperture is like the window. The bigger the window, the larger the aperture, which means more light gets in. More light means you can see the room better. The size of the aperture is measured in f-stops. The smaller the f-stop, the larger the aperture.

The ISO value is how a flim reacts to light shining on it. Some film is very sensitive to light and some are not.

Smaller aperture makes more of the picture stay in focus. If you want to take pictures of things moving fast(sports photographers) then you want quick shutter speed. Quick shutter speeds require smaller f-stops(larger aperture) to let more light in. If the aperture is not large enough and the shutter speed is too fast, the picture would be dark because it did not let enough light in to capture the picture.


Computer parts and what they do.

A computer has many parts and each part has its own job. Lets pretend that a computer is a person.

CPU: The CPU is like the brain. It does all the thinking and makes everything work. The CPU controls all the other parts in the computer. Just like your brain controls your body.

Motherboard: The motherboard is like the skin and skeleton of the computer. It holds every part together and makes sure each part can work with one another.

RAM: RAM is like the hands of the human body. If a person has more hands, they can do more things at once and multitask more efficiently. If someone has a job that requires two hands but they only have one hand, it will slow them down. But if a job requires one hand and the person has four hands, then it is pointless to have a lot of hands. Every program on your computer takes up RAM. More RAM = more programs can run at the same time more efficiently. RAM is measured in GB, and it is usually from 1GB to 8GB.

Power Supply: The power supply is like the heart. Just like the heart has to pump blood throughout the body, the power supply has to make sure there is enough power for all the parts in the computer or it will not work. Power supplies are measured in watts and are usually anywhere between 300W all the way up to 800W+.

Hard Drive: A hard drive is like a huge backpack that is being worn at all times. It is where everything is stored. Pictures, movies, documents, are all stored in this backpack. The bigger the backpack, the more it could hold. Sometimes the backpack gets very messy because there is so much stuff in it so you would want to "defragment" it. What this does is it organizes everything in the backpack so it is easier to find stuff later. Hard drives are measured in GB and TB. 1000GB = 1TB.

Video Card: A video card is like the eyes of a person with very bad eyesight. It lets you see everything that is happening but it needs eyeglasses(monitor) to show you. Without the video card, you can't see what you're doing. The video card requires a lot of power and when playing video games and it can get very hot.

Monitor: The monitor is like eyeglasses. It lets you see everything that is happening. Without it, you can't see anything. The monitor is connected to the video card.

Network: The network is the persons phone, it can be a wired house phone or a wireless cell phone. It is how the person communicates to other people. How fast the person can talk to others depends on how fast the internet is.