Yi-YiEdward Yang

“We never live the same day twice.”

So what’s the sameabout yesterday and today?

Circumstances, behaviors and systems that make them possible.

ConnectionsBBC, James Burke

Systems

Objects can seemingly exist in isolation physically,

but are actually often connected to other thingsthrough relationships.

Example:Food (cheesesteak sandwich)

$6

Chapter 1

Systems

ElementsInterrelationsFunction/Purpose

Systems

StocksFlows

Reading Assignment

Skim Chapter 2Read Chapters 3-6

Example Systems

Personal Finances

Every month, Zulari is paid $2000 by direct deposit to his savings account, and his employer makes a contribution of $200 to Zulari’s retirement account. He then moves some money from his savings account into his checking account to pay his rent ($800) and credit card bills (typically around $400) and the checking account fee ($10/month). If possible, Zulari moves some of the remaining money from his savings account to his retirement account. The rest he keeps in his savings account which has an interest rate of 1.5%.

What does this system look like?

Acid Rain

Rain of pH 3.5 periodically falls on a pond that has a pH level of about 7.

After 6 months, the pond water pH is still about 7.

After a year, the pond water pH has dropped to about 5.5.

What does this system look like?

What could explain the behavior?

Metabolism

We regularly get energy from food,and expend energy on various activities.

Albert running(to class)

90 Cal in 10 min3/5 Twinkie

What does this system look like?

Boundaries, mental and “actual”

Example: Perfluorinated Compounds

1/26/12 9:54 AMStudy Links PFC Exposure to Impaired Immune Function in Kids : Shots - Health Blog : NPR

Page 1 of 2http://www.npr.org/blogs/health/2012/01/24/145745691/common-chemicals-could-make-kids-vaccines-less-effective

Common Chemicals Could Make Kids'Vaccines Less Effective

by JON HAMILTON

04:05 pmJanuary 24, 2012

The more exposure children have to chemicals called perfluorinated compounds, theless likely they are to have a good immune response to vaccinations, a study justpublished in JAMA, the Journal of the American Medical Association shows.

The finding suggests, but doesn't prove, that these chemicals can affect the immunesystem enough to make some children more vulnerable to infectious diseases.

For decades now, PFCs have been used in nonstick coatings, stain-resistant fabricsand some food packaging. And because they persist in the environment for years,they have become common around the globe.

"You can find them in polar bears," says Dr. Philippe Grandjean, the study's leadauthor who works at both Harvard and the University of Southern Denmark.

Studies in animals have shown that PFCs can weaken the immune system.

Grandjean wanted to know whether this was happening in children. So he led a teamthat studied nearly 600 kids in the Faroe Islands, which lie about halfway betweenScotland and Iceland.

The Faroese have levels of PFCs similar to those of U.S. residents. Grandjean figuredif the chemicals were having an effect, it would show up in the way kids' bodiesresponded to vaccinations.

Normally, a vaccine causes the production of lots of antibodies to a specific germ.But Grandjean says the response to tetanus and diphtheria vaccines was much

Stig Nygaard/FlickrEven in the remote Faroe Islands, some children have high levels of perfluorinated compounds in their blood. The chemicalsmay interfere with the immune system.

http://www.npr.org/blogs/health/2012/01/24/145745691/common-chemicals-could-make-kids-vaccines-less-effective

What can be thought of as an isolated system(manufacturing with PFCs)is much more complex.

At least two (sub)systems:

Industrial ManufacturingHuman Immune System

And potentially many more:

Human BodyEcosystemsWaste ManagementEconomic Systems

Example: Environmental Impact of a Water Treatment Facility