Friday, August 2, 2013

Twins 08.02.13

My girls are 7 months old today and very different. Rain is intense in her attention to things and small details, she is quiet and is always off exploring (even though she only scoots and rolls). Sometimes she squeaks when she is excited, she doesn't like sweet food as much as veggies. Her favorites are peas and plain cereal. Rain was the first to escape from the car seat when she's not strapped in and the first to figure out how to hold her own bottle. She's always examining objects and even her own hands just to see how they work. Today I watched her examine a Lego block for a good twenty minutes, just rolling it around putting her hand and fingers in all the holes.

River is more vocal and always wants to be the center of attention, where Rain examines new things River shakes them and tries to get them to make noise. She was the first to vocalize and giggle, her belly is ticklish too. River also growls at people and things, not an angry growl but just a very guttural sound, it's very comical, like a tiny dinosaur trying to be heard. She loves juice and the sweet fruity foods, when she doesn't want to eat something she blows raspberries to get it out of her mouth. Today while I was feeding her and Rain mixed veggies she blew most of it out and I got more on me then she ate. River is goofy, personable and loves to cuddle.

It's crazy to see how different they are. Rain is the little scientist trying to figure out how the world works and River is the social butterfly trying to mimic the big people.

Algebra 08.02.13

The last part of lesson two focuses on exponents. When a dealing with several variables multiplied together that have exponents the exponents can be added together to simplify the expression. For example if I have x^2*y^4*x^9*3 (where ^ is used to show there is an exponent) I can simplify to x^11*y^4*3.

Lesson three is about polynomials. The distributive property allows us to take the expression a(b+c) and simplify it to ab+ac. For example say we have the expression 5-(6-x) we can think of the negative sign as a -1 and distribute it to get 5-6+x or -1+x. When multiplying polynomials together make sure to multiply every term in the first polynomial by every term in the second polynomial. For example (x+2)(x+5)= x^2+5x+2x+10 which simplified is x^2+7x+10.

Thursday, August 1, 2013

Algebra 08.01.13

Lesson 2 in Udacity's College Algebra course is about expressions. It starts by going back over the commutative property of both addition and multiplication. As a reminder the commutative property just means that the order of terms or factors doesn't matter. So a+b+c is the same thing as b+a+c and a*b*c is the same as c*a*b and so on. When combining like terms it is important to remember that they need to have the same variable and power (x cannot be added to x squared). So 2x+3x+4-2y can be simplified to 5x-2y+4 but no further.

A polynomial is an expression with constants and/or variables that are combined using addition, subtraction and multiplication, where all exponents are non-negative integers. The degree of a term is the sum of exponents on the variables in that term. So x squared times y cubed would have a degree of 5 because the exponents 2 and 3 add up to 5. The degree of a polynomial is equal to the highest degree of any of its terms. the standard form of a polynomial is to put the terms in order from highest degree to lowest degree.

Psychology 08.01.13

So over the last few days I have been working on Lesson 3 "The Biology of Behavior". Last post I talked about colorblindness which is a trait controlled by one gene. There are, however, many traits that are controlled by multiple genes such as eye color or height, these are called polygenic traits.  Traits are not just affected by genes but also by the environment. Identical twins can posses very different traits because of their life choices, if one overeats and smokes while the other doesn't  they are going to look very different. Epigenetics is the study of how our environment can turn different traits on and off. There is a study about two genetically identical mice whose mothers were fed different diets while pregnant, one high in methyl groups and one without. The end result was that one mouse came out obese and yellow while the other was normal and brown. These mice have the same genotype but different phenotypes. The same principals hold true for personality traits, there is a gene that is referred to as the warrior gene, this gene was thought to cause aggressive behavior but as it turns out many people have the gene without displaying aggressive behavior. In fact it takes an abusive childhood coupled with the Monoamine Oxidase A (warrior gene) to cause the more aggressive personality, making this an excellent example of how the environment can affect the gene expression.

The next part of Lesson 3 had to do with the nervous system. The nervous system can be broken down as into the Central and Peripheral nervous systems. The central nervous system consists of the brain and spinal cord while the peripheral accounts for all the other nerves. The peripheral system can be broken into the somatic and autonomic systems, the autonomic system controls functions like heart beat, breathing, digestion etc... the somatic is responsible for voluntary functions. Both of these systems have motor and sensory nerves. The autonomic nervous system has both a sympathetic and parasympathetic nervous system.   The sympathetic nervous system is responsible for the fight or flight response, when activated it does things like dilate the pupils, increase heart rate, inhibit digestion and relax the bronchi to make taking in more oxygen possible. When the parasympathetic nervous system is activated it has the opposite effect, the pupils and bronchi are restricted, heart rate is slowed and digestion is stimulated.

There are two types of cells that make up the nervous system, Glial cells and Neurons. Glial cells provide structural support and remove debris while Neurons process and transmit information. There are three different types of neurons; sensory, motor and interneurons, the interneurons connect neurons to one another. Below is a very rough drawing of a neuron. The Soma is the center of the cell and contains the nucleus. Branching off of the soma are the Dendrites, dendrites connect to other neurons and are the receivers for the cell. The axon transmits the electrical charge (when a neuron fires) to the terminal buttons, the mylin sheath (not present on all neurons) helps to speed up this process. The terminal buttons release neurotransmitters to neighboring neurons and the process repeats. Neurotransmitters can be either inhibitory or excitatory, excitatory neurotransmitters increase the chance that a neuron will fire while inhibitory ones decrease that chance. So to put it all together lets say an excitatory neurotransmitter is received by the dendrites of a neuron, if enough are received the neuron will fire off an electrical signal that runs down the axon and tells the terminal buttons to release more neurotransmitters once they do the cycle repeats with the next neuron.