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HAZEL SIVE: All right. After your class exercise that has to do with vectors and ligation, you should be able to find compatible ends and figure out whether or not they will ligate or not. And you should understand the concept of a vector and how this is used to carry a piece of DNA and to amplify a piece of DNA that you are interested in. I want now to move to our last topic in this discussion today. And that has got the acronym, or the abbreviation, PCR. PCR stands for polymerase chain reaction, polymerase chain reaction, PCR. And it is a very cool technique that allows one to exponentially amplify DNA in a test tube in the lab. Exponential amplification or synthesis of DNA in the lab-- why do we care about this? Why is PCR of interest? It's of interest because it means that you can take a tiny, tiny amount of starting DNA and you can make lots, and lots, and lots, and huge amounts of it. When we talked about molecular cloning, you also amplify DNA a great deal. But...

After our warm-up, we can now come to the real problem. We have, again, a random variable Theta with a known prior distribution. And we're interested in a point estimate. What will be different this time, however, is that we now have an observation. And we also have a model of that observation as a conditional distribution given the value of the true parameter. We observe a value of that random variable. That value is little x. And on the basis of that value, we would like to now come up with a point estimate of the unknown random variable Theta. How do we proceed? We can, of course, use the Bayes rule. And the Bayes rule is going to give us a distribution for the unknown random variable given the observation that we have obtained. And that distribution could be discrete or continuous. Let me just plot something as if it's continuous. And now that we have the posterior distribution of Theta, we would like to come up with a point estimate. How do we do it? Remember...

How long after swallowing a pill does it takes for a drug to enter your bloodstream? How long does it take for hot molten glass to cool? In this video, we'll see how the gradient helps us model molecular and thermal diffusion. This video is part of the Differential Equations video series. Laws that govern a system's properties can be modeled using differential equations. Hi, my name is Tom Peacock, and I'm a Professor of Mechanical Engineering here at MIT. Today I'd like to talk to you a little bit about the gradient. Partial differential equations describe the world around us. And partial differential equations often contain grad, div, and/or curl terms. In order to use these operations to describe physical phenomena, the first step is to understand what each mathematical process means geometrically and how it behaves in different examples. The gradient is an operation that takes in a scalar function and outputs a vector field. Many scalar quantities such...

Soon after a meal, your digestive system breaks down the food you have eaten into a simple sugar called glucose. Glucose is absorbed from the gut into the bloodstream, causing your blood sugar level to increase. In healthy individuals, feedback mechanisms in the body bring blood sugar levels back to normal. In some people, this process breaks down, resulting in diabetes. In this video, we'll take a closer look at feedback loops, how they tie into the body's mechanism of internal regulation, and what happens when these mechanisms fail. This video is part of the Information Flow series. A system is shaped and changed by the nature and flow of information into, within, and out of the system. Hi, my name is Leah Okumura and I am a Technical Instructor in the Biology Department at MIT. Before watching this video, you should be familiar with the concept that your body is a tightly regulated environment. After watching this video, you will be able identify the general co...