Some on the eye

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Some on the eye

• Myopia Near sightedness
• The image focuses in front of the retina

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Pathology of myopia varies

• Japan -44 of adult pop.
• U.S. 20-25 of adults
• Reading and education level
• Are risk factors
• During one of the Chinese revolutions, they
  killed people with glasses because it meant they
  had read

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Hyperopia

• Farsightedness
• At times confused with loss of vision at onset of
  age
• Note ostrich eyes are bigger than its brain

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Ostriches are ridiculous
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Presbyopia

• Greek Presby old person
• Theory is that with age the crystallin lens loses
  elasticity.
• Become far sited
• So they get bifocals
• Ben Franklin

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Astigmatism

• defect of the eye, where vision is blurred by an
  irregularly shaped cornea.
• A refractive problem
• Might be able to focus in horizontal plane, but
  not vertical

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Evolution of the Eye

• Homologous organ
• First eyes 540 mya
• arms race idea

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• Adaptation Birds have better vision
• Night birds can pick up U.V. Light
• Euglena bacteria has a light sensitive patch (2)
• Planarians have eyespots

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• Is it too complex to evolve piece by piece?
• what good is half an eye?
• Argument from personal belief
• But there are a lot of sub optimal eyes in
  nature.
• Even in people a myopic person has an advantage
  over the blind.
• Humans dont have the best eyes by a long shot
• The mantis shrimp has eyes divided into three
  parts trinocular vision.
• We have 4 visual pigments, they have 16. Can
  pick up U.V. and polarized light

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Sea Sickness

• In Part results from your brain focusing on
  stable side of boat, waves moving closs, and
  waves moving far away on the horizon.

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Decibels

• Logarithmic unit, measures sound levels
• Originally a bell was the amount of sound lost
  over 1 mile of telephone line

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Ear Wax

• Cerumen
• Cleans, lubricates (prevents itching), and
  protects
• From sebaceous and apocrine glands
• Two genetic types Wet Dominant, Dry recessive
• Asians, Am Indians Dry
• Africans, Europeans Wet
• Builds up in whales like rings in a tree

Wet type ear wax flouresces under U.V. light
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Taste Smell Chemical senses
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• McDonalds Fries
• Win best taste competitions
• Not the method, potatoes, or machinery
• Taste of fried foods determined by cooking oil
• McDs uses 7 cottonseed oil, 93 beef tallow a
  fry has more beef fat/ oz than a burger
• McDs world
• locations ?

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Obviously there was criticism

• McDs changed to pure veg. oil 1990
• Problem how to make them taste like beef without
  using beef?
• natural flavor
• Explains why most of our food taste the way it
  does.

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Natural Flavor vs. Artificial Flavor

• Both are man made
• 90 of our food is for processed food
• Canning, freezing, dehydrating destroy flavor
• Big money in making flavor
• Name food brands
• Name the companies that makes flavor

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International Flavors Fragrances (IFF)

• Worlds largest flavor company
• Also makes smell of best selling perfumes,
  deodorant, and soaps
• 2005 1.9 Bil.
• Givaudan 2nd
• Haarman Reimer Largest German
• Takasago Largest Japanese

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Smell owns taste

• Aroma can be 90 of a foods flavor
• What evolutionary benefit would organisms with a
  better sense of smell have?
• Find food
• Distinguish good food from bad

Evolution puts pressure on us.
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Flavors vs. smells

• Taste buds can detect 5 basic flavors
• Sweet, sour, bitter, salty, astringent, umami
• About 4-10K taste buds on tongue, cheek, pharynx,
  epiglottis
• Bumps called papillae
• Olfactory system can percieve thousands of
  different chemicals

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Mastication releases gases

• Thin layer of nerve cells called olfactory
  epithelium receives gases and transduces them
  into smell signals
• Brain combines smells signals with simple taste
  signals and decides if its something you want to
  eat.

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Food preferences personality form early in life

• Babies will adjust to hot spicy, bland health
  food, or fast food depending on what the people
  around them eat.

Baby eating sushi
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We dont know it all yet

• Psychosomatic effects happen
• Color of food can determine perception of its
  taste
• People can grow accustomed to bad smells.
• Come back from a long vacation and immediately
  take a good whiff of what your house smells like.
  Other people smell that whenever they visit you

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Aroma memory

• Nerve signals for smell go right past parts of
  our brain associated with memory.
• Smelling salts (ammonium carbonate can wake you
  up by causing an inhalation reflex
• Smells can bring back memories
• Comfort foods
• McDs makes billions on this (Happy Meals)

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Flavor in history

• Empires built, seas crossed, religions and
  philosophies changed over taste.
• Columbus went looking for flavor
• Salzburg Germany Founded to protect salt trade
• Saffron is 12 a gram

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• So artificial flavors cropped up from perfume
  companies after canning started
• German scientist playing with chemicals suddenly
  lab smells like grapes ? methyl anthranilate ?
  grape Kool-Aid? purplesaurus rex

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1.4 Bil a year

• 10K new food products a year
• 9/10 fail

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Tech

• Spectrometers
• Gas chromatographs
• Vapor detectors
• Can discern chemicals at 1 ppb
• Human nose can tell 0.000000000003
• Dogs better still

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Complex flavors

• Coffee, roast beast, strawberries thousands of
  chemicals at once
• Chemical responsible for flavor of Bell pepper
  only need 0.02 ppb a drop could flavor a
  swimming pool
• And its cheap flavor in 12oz of Coke ½ cent

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• Often though, 1 chemical provides the over-riding
  sense of the food.
• Ethyl-2-methyl butyrate apple
• Methyl-2-peridylketone popcorn
• Ethyl-3-hydroxybutanoate marshmallow
• Hexanal fresh cut grass
• 3-methyl butanoic acid B.O.

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So what?So natural flavor means its made using
old technology

• Natural
• Getting amyl acetate from distilling bananas with
  a solvent

• Artificial
• Getting amyl acetate from mixing vinegar with
  amyl alcohol, adding H2SO4 as a catalyst

Both taste exactly the same, both happen in the
same factory, but people want to see natural on
their label.
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Art or Science?

• Mouthfeel Its not just flavor,
• TA.XT2i Texture analyzer uses 250 probes to
  create an artificial mouth that senses bounce,
  creep, crunch, density, chewiness, gumminess,
  lumpiness, rubberiness, slipperiness, softness,
  wetness, spread, spring-back, tackiness
• How do you juggle all of this with subtleties of
  flavor?

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Genetics

• Dominant gene
• Phenylthiocarbamide, also known as PTC, or
  phenylthiourea tastes very bitter or not at all
  depending on genetics
• Discovered when a guy at duPont accidently
  spilled a bunch of crystalline PTC, some
  complained, some did not
• May explain why some people are more offended by
  cig. smoke

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Super Taster

• 25 of people of European dissent
• Maybe more fungiform papillae
• Linked to food preference, body type
• Coffee, alcohol, may be too intense
• Olives too salty

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Things go horribly awry

• Ageusia (pronounced ay-GOO-see-uh) Loss of sense
  of taste
• From neural damage
• anosmia - a loss of the sense of smell.
• Cold
• Parkinsons
• Alzheimer's