Prion diseases are caused by malformed proteins that can also malform the normal versions of themselves. When they do this in the central nervous system, they cause brain damage and death. In humans, Creutzfeldt-Jakob disease is probably the most well-known for its relation to the version found in cows, bovine spongiform encephalopathy, also known as "mad cow disease."
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30 May 2010
29 May 2010
Animal Communication: What, How, and Why
Animals communicate in many myriad ways that are as diverse as the animals themselves. They communicate for a variety of reasons. Some examples are to attract mates, threaten rivals, warn about danger, or share information about food sources. The different ways in which animals communicate can be visual, audial, or chemical (smell or taste). For highly social species, there may be facial expressions, body language, or dances.
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02 May 2010
Beginner's Guide to Facebook Game Castle Age
Castle Age is a Facebook game with a fantasy theme. There are quests, heroes, generals which are heroes that lead quests, demi powers which aren't heroes, and tribute-paying to the demi powers which gives you bonuses and unlocks more quests. There are lands, soldiers, weapons, armor, and magical powers. There are alchemy ingredients, some of which are also soldiers, weapons, armor, or magical powers. There are battles with other players and battles with monsters. There are experience points, upgrade points, demi points, battle points, and favor points. There are three separate ways to add your friends to the game.
In short, there are lots of buttons to do lots of different things, lots of characters and items and tabs for things everywhere, and it can all be very confusing when you've just started.
Guide to Castle Age: Overview of Game Layout and Points
Guide to Castle Age: Hints and Tips About Quests, Items, and Characters
Guide to Castle Age: Hints and Tips About Friends, Battles, and Monsters
In short, there are lots of buttons to do lots of different things, lots of characters and items and tabs for things everywhere, and it can all be very confusing when you've just started.
Guide to Castle Age: Overview of Game Layout and Points
Guide to Castle Age: Hints and Tips About Quests, Items, and Characters
Guide to Castle Age: Hints and Tips About Friends, Battles, and Monsters
01 May 2010
Calculating Rotational Kinetic Energy
Rotational kinetic energy is the amount of energy that an object has while going around in a circle. To calculate it, you will need to know two things: its angular velocity (i.e., how fast it's going around in a circle) and its moment of inertia (i.e., inertia while going in a circle).
Step 1: Weigh the object to get its mass in kilograms. We'll call it "m."
Step 2: Measure the distance between the object and the center of rotation. The center of rotation is the point that the object is circling. For example, if you have a ball on the end of a string that you're twirling over your head, the center of rotation would be your hand and the distance would be the length of string between your hand and the ball. We'll call this distance "r." You'll want this in meters.
Step 3: Calculate moment of inertia. Multiply mass by distance squared: I = m * r2.
Step 4: Measure how long it takes, in seconds, for the object to make one complete circle around the center of rotation. This is angular velocity in revolutions per second. For simple objects like a ball on the end of a string, you can use a stopwatch. If you prefer to make the measurement in revolutions per minute (RPM), you will need to divide by 60 to convert to seconds.
Step 5: Convert angular velocity into radians per second. A full circle is 2 * π radians, or about 6.28318 radians. If it takes one second for the object to make one full circle, the angular velocity would be 6.28318 radians per second. One RPM would be 6.28318 divided by 60, or 0.1047 radians per second. We'll call this "w."
Step 6: Multiply moment of inertia by angular velocity squared, then divide by two to arrive at the answer: RKE = I * w2 * 1/2. This gives you the rotational kinetic energy in joules. One joule is equal to one (kilogram * meter2) / second2.
Tips
You can weigh the object in pounds and ounces, and measure the distance in feet and inches, then convert to kilograms and meters before continuing.
Warnings
This is the generalized form of the equation. It assumes that all of the object's mass is at the same distance from the center of rotation. This works well for items at the end of a string or hoop objects like bicycle wheels. If different parts are at different distances, you will need to calculate moment of inertia separately for each, then add them all together for a total. If it's a solid object spinning around an axis rather than lots of parts circling a point, you will need to use calculus--however, there are some equations for the more common types of objects in the third reference listed.
Additional resources from C.R. Nave's Hyperphysics:
Rotational Kinetic Energy
Angular Velocity
Moment of Inertia
Step 1: Weigh the object to get its mass in kilograms. We'll call it "m."
Step 2: Measure the distance between the object and the center of rotation. The center of rotation is the point that the object is circling. For example, if you have a ball on the end of a string that you're twirling over your head, the center of rotation would be your hand and the distance would be the length of string between your hand and the ball. We'll call this distance "r." You'll want this in meters.
Step 3: Calculate moment of inertia. Multiply mass by distance squared: I = m * r2.
Step 4: Measure how long it takes, in seconds, for the object to make one complete circle around the center of rotation. This is angular velocity in revolutions per second. For simple objects like a ball on the end of a string, you can use a stopwatch. If you prefer to make the measurement in revolutions per minute (RPM), you will need to divide by 60 to convert to seconds.
Step 5: Convert angular velocity into radians per second. A full circle is 2 * π radians, or about 6.28318 radians. If it takes one second for the object to make one full circle, the angular velocity would be 6.28318 radians per second. One RPM would be 6.28318 divided by 60, or 0.1047 radians per second. We'll call this "w."
Step 6: Multiply moment of inertia by angular velocity squared, then divide by two to arrive at the answer: RKE = I * w2 * 1/2. This gives you the rotational kinetic energy in joules. One joule is equal to one (kilogram * meter2) / second2.
Tips
You can weigh the object in pounds and ounces, and measure the distance in feet and inches, then convert to kilograms and meters before continuing.
Warnings
This is the generalized form of the equation. It assumes that all of the object's mass is at the same distance from the center of rotation. This works well for items at the end of a string or hoop objects like bicycle wheels. If different parts are at different distances, you will need to calculate moment of inertia separately for each, then add them all together for a total. If it's a solid object spinning around an axis rather than lots of parts circling a point, you will need to use calculus--however, there are some equations for the more common types of objects in the third reference listed.
Additional resources from C.R. Nave's Hyperphysics:
Rotational Kinetic Energy
Angular Velocity
Moment of Inertia
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