Just brought out of the archives...notes from April 9th.
This is a day when I was considerably late to class (in large part due to a screwy RTS schedule, but let's not go there)
On this day, Jeff (Pelz) and Andy (Herbert), the Vision and Mind lecturers respectively, came in to answer some of our questions.
This is based on the notes from another student who was there the whole time; while looking at the notes, I am trying to convert her note style into mine.
----------
* The world is broken down into little pictures, which your brain then puts together
* Since the system as a whole is so complex,. it helps to look at simple individual signals
* Yet, how does the brain combine these inputs into what is perceived as a smooth image? We don't know.
There exists something called the "binding problem" - action potentials [of the signals a neuron sends] are all-or-nothing, so the rate code (data speed and built in redundancy) is important
----------
[Editor's note: The following section has to do with a question I brought up often during this topic; i.e. what happens when something goes wrong in the system; and conversely, when someone has a sensory deficiency, what brain components are malfunctioning?
The prominent existence of NTID here at RIT has brought this type of question to the forefront of my mind. (yes, I know that the topic refers/referred to vision problems, but that is something I commonly find, that one topic jogs my memory on a somewhat-related topic. Furthermore, I recall from the lectures that several sensory areas are located in the same brain lobe, implying to me that they have interconnected or similar functions.)
Colorblindness was the main thing discussed in response to this question.
* With cataracts, the cornea is yellowing, warping the perception of certain wavelengths, especially on the blue end of the spectrum
* A lot of colorblindness has to do with errors in the retina's system of cones, which perceive color
** Some colorblind people don't have any, or the cones are not wired together properly
* Humans are trichromats, which perceive three different colors (R, G, B), and have different sets of cones that specialize in each. [this presumably in addition to light/dark white/black]. Soem humans are dichromats, which would logically mean a form of colorblindness compared to normal human perception.
Many animal species are bichromats or tetrachromats.
(At about this point of Andy & Jeff's talk, I show up and begin taking my own notes, that original post being located here: http://alan-labbook.blogspot.com/2008/04/questions-answered-by-andy-jeff.html)
[With the following comments, I'm not knocking the person who have me notes for 4/9, just stating facts/observations]
I notice that her style has more data fragments than mine does. (Granted, in the interest of keeping up the pace during the lectures, I often didn't use 100% complete sentences)
I find that different details are pulled out, but with the same general areas covered.
Note-taking is basically summarizing, and that's a task that different people ar eobviously going to approach differently.
Friday, May 16, 2008
Friday, May 9, 2008
Today's activity
Our tour guide - a Dr. Ferran
This is a bioscience research lab that I share with a couple other faculty
Dr. Sweet's aquarium - large amount of pencil urchins
She is a developmental biologist - studies organisms' gestation/etc.
Dr. Newman - human geneticist; studies generic patterns of age-related deafness
Human genetics & molecular analysis
Lots of collaboration in here with other people in the field
A lot undergraduate research assistants [they atleast get credit for it]
We don't run in to too many problems with the animal-welfare and religious-fanatic types
The Human Genome Project - provided a lot of raw data that we're just beginning to work with.
"Why couldn't God have released the source code with the binaries?" :P
More work needs to be done on proteins, though ("the devil's in the details.")
--------
We are now in cell-culture room
Not sterile but still above-average cleanliness
------
UV lightboxes have a sterilization effect
Some issue of our body contaminating the experiment, rather than the experiment contaminating us. (The types of pathogens we work with aren't seriously harmful to humans)
This is a bioscience research lab that I share with a couple other faculty
Dr. Sweet's aquarium - large amount of pencil urchins
She is a developmental biologist - studies organisms' gestation/etc.
Dr. Newman - human geneticist; studies generic patterns of age-related deafness
Human genetics & molecular analysis
Lots of collaboration in here with other people in the field
A lot undergraduate research assistants [they atleast get credit for it]
We don't run in to too many problems with the animal-welfare and religious-fanatic types
The Human Genome Project - provided a lot of raw data that we're just beginning to work with.
"Why couldn't God have released the source code with the binaries?" :P
More work needs to be done on proteins, though ("the devil's in the details.")
--------
We are now in cell-culture room
Not sterile but still above-average cleanliness
------
UV lightboxes have a sterilization effect
Some issue of our body contaminating the experiment, rather than the experiment contaminating us. (The types of pathogens we work with aren't seriously harmful to humans)
Thursday, May 8, 2008
Big Bang and Black Holes: Topic Outline
What is important about the Big Bang And Black Holes topic?
I'd say it goes something like this...
1) "In the beginning..."
1.1) Singularity of infinitely small volume (and thus infinitely high temperature and pressure
1.2) This exploded/expanded - that event is the Big Bang itself
2) How do we know?
2.1) Hubble's Law - universe is expanding
2.1.1) Illustrated by Redshift [Light wavelength changes thanks to a stretching of the medium - space)
2.1.2) Extrapolate this backwards, and the universe would have been infinitely small at one point.
2.2) Cosmic background radiation
2.2.1) Remnants of the Big Bang explosion
2.2.2) Residual temperature in the universe of a few degrees Kelvin
2.2.3) Small temperature variations in this radiation - matter clumps; this clumping eventually aggregated itself into galaxies
3) What happened after the Big Bang?
3.1) Freeze-out of the "fundamental forces" - strong force, electromagnetic force, weak force, gravity [They used to be of equal strength, now they aren't - I just listed them in strongest-to-weakest order]
3.2) Inflationary Period
3.2.1) Especially rapid period of expansion in early universe (< 1 sec after BB)
3.2.2) Without it, the early universe would have had to have been relatively larg ein order to have reached the current size
3.2) Energy to Matter
3.2.1) E = M * C^2 : energy can be converted to matter...energy takes up less space than matter
3.2.2) Balance of matter annihilating antimatter, eventually regular matter won out
3.2.2.1) We don't know why regular matter won out
3.2.3) Big Bang Nucleosynthesis
3.2.3.1) Roughly 3min after BB. Occurred at temperature of 10^9 Kelvin
3.2.3.1) Particles coalesced into atoms
3.2.3.2) BBN only would have lasted long enough to form light elements.
Universe is made up of predominately light elements, this lending support to this important part of the Big Bang model
Various isotopes of hydrogen, helium, lithium and beryllium were formed
3.3) Later, stars and galaxies develop
4) The Cosmological Principle: important concept
4.1) Isotropic: Large-scale structure looks the same in all directions
4.2) Homogenous: General physical properties of the universe are the same everywhere in it
Thus, the universe has no edge and no center
5) What are galaxies?
5.1) The Formation of Galaxies
5.1.1) Galaxies formed about 1 billion years after big bang
5.1.2) Hierarchical merging [smaller-scale version of this process likely forms solar systems]
5.2) Different galaxy shapes
5.2.1) Spiral - a disk with spiral arms. Our own Milky Way is one. Relatively small nuclear bulge. Relatively large amounts of young stars and star formation.
5.2.2) Elliptical - Dominated by spheroid. Relatively old
5.2.3) Irregular and Peculiar - Those terms mean what you think they mean. :)
5.3) Galaxy relations: Galaxy clusters, superclusters
5.3.1) Galaxies do gather into clusters
5.3.2) Supercluster Types
5.3.2.1) Rich - >1000 galaxies, giant central galaxy
5.3.2.2) Poor - 10 to 1000 galaxies, more spirals
5.3.2.3) Isolated galaxies - even more likely to be spirals
5.3.2) Galaxies in superclusters not gravitationally bound to each other
6) What are black holes?
A superdense object, to the point where its gravity is so strong that not even electromagnetic radiation [light] can escape
6.1) Fuller explanation of black holes is provided by Einstein's theories of relativity
6.1.1) Spacetime - space and time are connected (they are *relative* to each other)
6.1.2) Gravity is dependent on spacetime
6.1.3) Special relativity predicts/explains unusual behavior that occurs with abnormal values of space, time, and/or gravity
6.2) Now, if no electromagnetic radiation, visible light or otherwise, emerges from a black hole, how do we study them?
6.2.1) Their effect on visible bodies near them: For ionstance, a black hole may suck in gas from nearby stars
6.3) Black holes are the Las Vegases of the universe - what happens [goes into] in a black hole stays in a black hole.
6.3.1) This is how black holes build mass
6.3.2) Difference: Actions in Las Vegas may also cause alimony, child support or prison time to increase
7) Dark Matter and Dark Energy: The Monkey Wrench in the Cosmological Works
We don't know what it is; hence the name 'dark'.
Nonbaryonic ("Baryons" are a type of particle with protons and neutrons being the most notable examples of them)
7.1) Composes most of the universe
7.2) Dark matter:
7.3) Dark energy: even more "weird" than dark matter
-More to come-
I'd say it goes something like this...
1) "In the beginning..."
1.1) Singularity of infinitely small volume (and thus infinitely high temperature and pressure
1.2) This exploded/expanded - that event is the Big Bang itself
2) How do we know?
2.1) Hubble's Law - universe is expanding
2.1.1) Illustrated by Redshift [Light wavelength changes thanks to a stretching of the medium - space)
2.1.2) Extrapolate this backwards, and the universe would have been infinitely small at one point.
2.2) Cosmic background radiation
2.2.1) Remnants of the Big Bang explosion
2.2.2) Residual temperature in the universe of a few degrees Kelvin
2.2.3) Small temperature variations in this radiation - matter clumps; this clumping eventually aggregated itself into galaxies
3) What happened after the Big Bang?
3.1) Freeze-out of the "fundamental forces" - strong force, electromagnetic force, weak force, gravity [They used to be of equal strength, now they aren't - I just listed them in strongest-to-weakest order]
3.2) Inflationary Period
3.2.1) Especially rapid period of expansion in early universe (< 1 sec after BB)
3.2.2) Without it, the early universe would have had to have been relatively larg ein order to have reached the current size
3.2) Energy to Matter
3.2.1) E = M * C^2 : energy can be converted to matter...energy takes up less space than matter
3.2.2) Balance of matter annihilating antimatter, eventually regular matter won out
3.2.2.1) We don't know why regular matter won out
3.2.3) Big Bang Nucleosynthesis
3.2.3.1) Roughly 3min after BB. Occurred at temperature of 10^9 Kelvin
3.2.3.1) Particles coalesced into atoms
3.2.3.2) BBN only would have lasted long enough to form light elements.
Universe is made up of predominately light elements, this lending support to this important part of the Big Bang model
Various isotopes of hydrogen, helium, lithium and beryllium were formed
3.3) Later, stars and galaxies develop
4) The Cosmological Principle: important concept
4.1) Isotropic: Large-scale structure looks the same in all directions
4.2) Homogenous: General physical properties of the universe are the same everywhere in it
Thus, the universe has no edge and no center
5) What are galaxies?
5.1) The Formation of Galaxies
5.1.1) Galaxies formed about 1 billion years after big bang
5.1.2) Hierarchical merging [smaller-scale version of this process likely forms solar systems]
5.2) Different galaxy shapes
5.2.1) Spiral - a disk with spiral arms. Our own Milky Way is one. Relatively small nuclear bulge. Relatively large amounts of young stars and star formation.
5.2.2) Elliptical - Dominated by spheroid. Relatively old
5.2.3) Irregular and Peculiar - Those terms mean what you think they mean. :)
5.3) Galaxy relations: Galaxy clusters, superclusters
5.3.1) Galaxies do gather into clusters
5.3.2) Supercluster Types
5.3.2.1) Rich - >1000 galaxies, giant central galaxy
5.3.2.2) Poor - 10 to 1000 galaxies, more spirals
5.3.2.3) Isolated galaxies - even more likely to be spirals
5.3.2) Galaxies in superclusters not gravitationally bound to each other
6) What are black holes?
A superdense object, to the point where its gravity is so strong that not even electromagnetic radiation [light] can escape
6.1) Fuller explanation of black holes is provided by Einstein's theories of relativity
6.1.1) Spacetime - space and time are connected (they are *relative* to each other)
6.1.2) Gravity is dependent on spacetime
6.1.3) Special relativity predicts/explains unusual behavior that occurs with abnormal values of space, time, and/or gravity
6.2) Now, if no electromagnetic radiation, visible light or otherwise, emerges from a black hole, how do we study them?
6.2.1) Their effect on visible bodies near them: For ionstance, a black hole may suck in gas from nearby stars
6.3) Black holes are the Las Vegases of the universe - what happens [goes into] in a black hole stays in a black hole.
6.3.1) This is how black holes build mass
6.3.2) Difference: Actions in Las Vegas may also cause alimony, child support or prison time to increase
7) Dark Matter and Dark Energy: The Monkey Wrench in the Cosmological Works
We don't know what it is; hence the name 'dark'.
Nonbaryonic ("Baryons" are a type of particle with protons and neutrons being the most notable examples of them)
7.1) Composes most of the universe
7.2) Dark matter:
7.3) Dark energy: even more "weird" than dark matter
-More to come-
Wednesday, May 7, 2008
Visit to Jeff Pelz in his image lab
Wearable eye tracker vs. lab-based eye trackers
* In-lab: Purkinje eye trackers: Purkinje is reflections off of the eye, a "glint in someone's eye"
* Investigate different questions in different envirnoments
* Limitations of the lab: people may behave differently in a lab environment, and Perkingi trackers require the head to be immobilized
* In-lab equipment has faster frequency and higher accuracy
* SOme equipment is based on video cameras rather than eye-trackers
When reading: small smooth movement ( a word) with jumps to the next word and the next line. Sometimes regression moments to rereread something
In our terms, a "gaze" is when you look at one object, rather than an entire scene, but w/o keeping your head/eyes totally still
Modeling gaze: what you fixate on in an image, how long, and why. | By modeling gaze, build a model of what you think people will look at, and compare it with experimental data
In 1/10 of a second, you get the general idea of an image (i.e "This is a kitchen")
bottom-up: start with pixels and then form a concept
top-down: start looking for a concept and then doscover the details [i.e. pixels]
For top-down you need to have an understanding of the concept you are looking for
* In-lab: Purkinje eye trackers: Purkinje is reflections off of the eye, a "glint in someone's eye"
* Investigate different questions in different envirnoments
* Limitations of the lab: people may behave differently in a lab environment, and Perkingi trackers require the head to be immobilized
* In-lab equipment has faster frequency and higher accuracy
* SOme equipment is based on video cameras rather than eye-trackers
When reading: small smooth movement ( a word) with jumps to the next word and the next line. Sometimes regression moments to rereread something
In our terms, a "gaze" is when you look at one object, rather than an entire scene, but w/o keeping your head/eyes totally still
Modeling gaze: what you fixate on in an image, how long, and why. | By modeling gaze, build a model of what you think people will look at, and compare it with experimental data
In 1/10 of a second, you get the general idea of an image (i.e "This is a kitchen")
bottom-up: start with pixels and then form a concept
top-down: start looking for a concept and then doscover the details [i.e. pixels]
For top-down you need to have an understanding of the concept you are looking for
Friday, May 2, 2008
Notes from the semiconductor lab we visited last week [April 25th]
We visited a semiconductor facility a week ago; this is on the RIT campus as part of the engineering program's apparatus (specifically, Microelectronic Engineering)
The most obvious thing is the 'clean' in 'clean room', and some of the cleanliness measures employed were rather interesting.
It's a Class 1000 cleanroom, meaning them aim for less than 1000 particles per cubic foot.
For instance, outside laptops weren't allowed in (because of dust & related crud that may be in the keyboard), so this post is actually a rough transcription of my paper notes [plus some additional commentary on the lab].
For really hardcore microelectronics engineers, there's special paper that 'sheds' less particulates into the air.
The full-body suits were interesting and amusing-looking, we collectively looked like future astronauts or something.
Air pressure is slightly higher inside, so that clean air rushes out and dirty air doesn't rush in when access doors are opened
The day before our visit was "Bring your Son/Daughter To Work Day", and our tour guide remarked that the gaggle of 5-year-old present looked rather cute after bieng outfitte din the suits.
Sodium is a really bad contaminant. [editor's note: so no salty munchies in the lab!]
------------
Anyway, their equipment is sufficient to produce microchips from beginning to end, but it's all atleast a few years old. (and thanks to Moore's Law, that makes the chips quite out of date; but the value is there as an educational tool.) Furthermore, most of the equipment was donated by
big names in the field (such as IBM and Intel) after *they* upgraded.
Furthermore, consumer-photography companies like Canon, Nikon, and Kodak are also involved in this type of industrial equipment. [The photoresist process, important to semiconductor manufacture, does involve exposing the silicon wafer to a certain amount and type of light in certain areas of the chip.]
Makes sense in a way, because as is common for RIT, grads often end up going right work with one of the big-name companies in their field
-------
So, roughly speaking, how does the process actually work?
* A block of processed silicon is 'sliced' into wafers, and each of those wafers will become a large quantity of chips over the course of the manufacturing process. Thus, each batch of microchips necessarily contains a large number of individual chips.
* With lithography, a printing process, computer-designed patterns are put onto the wafer
* Then we apply photoresist; we apply it over certain parts of the wafer, so that some areas of the chip 'resist' when exposed to light and some won't [this forms the pattern]
* The photoresist is exposed by a certain wavelength of blue light from one of the lab's machines
To prevent accidental exposure, the lightbulbs in that area are yellow and the windows are tinted. I recognized this as being analogous to the use of red-colored lightbulbs in traditional photofilm darkrooms.
* Ion bombardment, towards the end of the process implants material into the wafer that makes it more conductive. (Yes, we discussed silicon for quite a while before mentioning implants. :))
------
Dangerous chemicals are important to the semiconductor process, but one sign in the lab touched upon this with a note of humor:
"You can walk on a wooden leg, you can eat with false teeth, but you can't see with a glass eye. So wear your safety glasses."
The most obvious thing is the 'clean' in 'clean room', and some of the cleanliness measures employed were rather interesting.
It's a Class 1000 cleanroom, meaning them aim for less than 1000 particles per cubic foot.
For instance, outside laptops weren't allowed in (because of dust & related crud that may be in the keyboard), so this post is actually a rough transcription of my paper notes [plus some additional commentary on the lab].
For really hardcore microelectronics engineers, there's special paper that 'sheds' less particulates into the air.
The full-body suits were interesting and amusing-looking, we collectively looked like future astronauts or something.
Air pressure is slightly higher inside, so that clean air rushes out and dirty air doesn't rush in when access doors are opened
The day before our visit was "Bring your Son/Daughter To Work Day", and our tour guide remarked that the gaggle of 5-year-old present looked rather cute after bieng outfitte din the suits.
Sodium is a really bad contaminant. [editor's note: so no salty munchies in the lab!]
------------
Anyway, their equipment is sufficient to produce microchips from beginning to end, but it's all atleast a few years old. (and thanks to Moore's Law, that makes the chips quite out of date; but the value is there as an educational tool.) Furthermore, most of the equipment was donated by
big names in the field (such as IBM and Intel) after *they* upgraded.
Furthermore, consumer-photography companies like Canon, Nikon, and Kodak are also involved in this type of industrial equipment. [The photoresist process, important to semiconductor manufacture, does involve exposing the silicon wafer to a certain amount and type of light in certain areas of the chip.]
Makes sense in a way, because as is common for RIT, grads often end up going right work with one of the big-name companies in their field
-------
So, roughly speaking, how does the process actually work?
* A block of processed silicon is 'sliced' into wafers, and each of those wafers will become a large quantity of chips over the course of the manufacturing process. Thus, each batch of microchips necessarily contains a large number of individual chips.
* With lithography, a printing process, computer-designed patterns are put onto the wafer
* Then we apply photoresist; we apply it over certain parts of the wafer, so that some areas of the chip 'resist' when exposed to light and some won't [this forms the pattern]
* The photoresist is exposed by a certain wavelength of blue light from one of the lab's machines
To prevent accidental exposure, the lightbulbs in that area are yellow and the windows are tinted. I recognized this as being analogous to the use of red-colored lightbulbs in traditional photofilm darkrooms.
* Ion bombardment, towards the end of the process implants material into the wafer that makes it more conductive. (Yes, we discussed silicon for quite a while before mentioning implants. :))
------
Dangerous chemicals are important to the semiconductor process, but one sign in the lab touched upon this with a note of humor:
"You can walk on a wooden leg, you can eat with false teeth, but you can't see with a glass eye. So wear your safety glasses."
Wednesday, April 30, 2008
Personal Interest Presentation: outline-in-progress
I'll edit this post as I develop more ideas for my outline
"Space, the final NanoPower frontier"
[Insert badly photoshopped picture of the Enterprise]
0)
Nanotech has potential in all areas of space exploration.
Nanotech will not immediately create new fields/devices, but rather, it has the potential to greatly improve existing devices. (especially in the near future)
0.1) Short overview of why we should be trying to use nanotubes (reference their positive charcteristics)
1) Existing use of nanotech in space
1.1) Space Nanotechnology laboratory at MIT (snl.mit.edu) has used nanotehc to build nanoscale components of NASA observers [Chandra X-Ray and others]
2) Nanoelectrical systems
2.1) Power systems, PMAD [Power Management and Distribution] systems
2.1.1) Applications in nuclear powersystems
2.1.2) Applications in solar powersystems
2.2) MEMS [Microelectromagnetic systems]: Combine microchips with electronics that would use them.
2.2.1) Important spacecraft electronics could be made smaller.
2.2.2) Micro-probes for imaging extraterrestrial objects
3) Nanocomposites as a spacecraft building material
3.1) "Armoring" against space debris
3.2) Useful in dealing with stresses of launch?
4) Types of space exploration; usage of nanotechnologies there
4.1) Deep-space travel
4.2) Colonization of extraterrestrial worlds
4.3) Surface exploration [using nanotech]
4.3.1) by humans
4.3.2) by probes/robots
4.3.2.1) Nanotechnology could enable you to build very small probes.
5) Use of nanotubes to transport stuff from Earth to low-Earth orbit
5.1) A space elevator?
5.1.1) Exciting theoretical possibility, but even the theory isn't completely ironed out yet.
* Many parts of this presentation will reference concepts discussed during Ryne Rafaelle's two presentations way back in Week 2. My notes are on this blog, and I still have access to the powerpoints, so memory of that material shouldn't be an issue.
"Space, the final NanoPower frontier"
[Insert badly photoshopped picture of the Enterprise]
0)
Nanotech has potential in all areas of space exploration.
Nanotech will not immediately create new fields/devices, but rather, it has the potential to greatly improve existing devices. (especially in the near future)
0.1) Short overview of why we should be trying to use nanotubes (reference their positive charcteristics)
1) Existing use of nanotech in space
1.1) Space Nanotechnology laboratory at MIT (snl.mit.edu) has used nanotehc to build nanoscale components of NASA observers [Chandra X-Ray and others]
2) Nanoelectrical systems
2.1) Power systems, PMAD [Power Management and Distribution] systems
2.1.1) Applications in nuclear powersystems
2.1.2) Applications in solar powersystems
2.2) MEMS [Microelectromagnetic systems]: Combine microchips with electronics that would use them.
2.2.1) Important spacecraft electronics could be made smaller.
2.2.2) Micro-probes for imaging extraterrestrial objects
3) Nanocomposites as a spacecraft building material
3.1) "Armoring" against space debris
3.2) Useful in dealing with stresses of launch?
4) Types of space exploration; usage of nanotechnologies there
4.1) Deep-space travel
4.2) Colonization of extraterrestrial worlds
4.3) Surface exploration [using nanotech]
4.3.1) by humans
4.3.2) by probes/robots
4.3.2.1) Nanotechnology could enable you to build very small probes.
5) Use of nanotubes to transport stuff from Earth to low-Earth orbit
5.1) A space elevator?
5.1.1) Exciting theoretical possibility, but even the theory isn't completely ironed out yet.
* Many parts of this presentation will reference concepts discussed during Ryne Rafaelle's two presentations way back in Week 2. My notes are on this blog, and I still have access to the powerpoints, so memory of that material shouldn't be an issue.
Personal Interest Presentation
This is the "final exam" for the Frontiers of Science class.
The idea here is to zoom on on sub-area(s) of any of the four topics covered, specifically sub-area(s) that especially interest you
I am focusing on the use of nanotechnology and NanoPower in current and future space exploration. To put it more lyrically,
"Space, the final NanoPower frontier"
To be honest, good sci-fi works can have quite a potential to be inspiring as to the course of scientific advancement.
A centerprice of our classroom is a widevision screen that, among other things, could display 4 PowerPoint-type slides at a time, and we have a PowerPoint template file designed to work with that.
The crux of my Personal Interest Presentation s going to be one of those, which is a process I've also used for the three topic summaries I've done to date.
The format is one I understand, and I'm also using it because I'll hopefully be able to focus on content rather on the logistical & production issues of a more exotic format
The idea here is to zoom on on sub-area(s) of any of the four topics covered, specifically sub-area(s) that especially interest you
I am focusing on the use of nanotechnology and NanoPower in current and future space exploration. To put it more lyrically,
"Space, the final NanoPower frontier"
To be honest, good sci-fi works can have quite a potential to be inspiring as to the course of scientific advancement.
A centerprice of our classroom is a widevision screen that, among other things, could display 4 PowerPoint-type slides at a time, and we have a PowerPoint template file designed to work with that.
The crux of my Personal Interest Presentation s going to be one of those, which is a process I've also used for the three topic summaries I've done to date.
The format is one I understand, and I'm also using it because I'll hopefully be able to focus on content rather on the logistical & production issues of a more exotic format
Monday, April 28, 2008
Medical Imaging
X-rays: very good for imaging bone, but not soft tissue
Still useful on kidneys - would see kidney stones
Before Roentgen's X-ray discovery, no way to look at body besides cutting it open
Some medical imaging methods (like X-ray) provide a picture, some (like ultrasound) provide a real-time picture
Where in the electromagnetic spectrum do we look?
Two parameters: resolution and attenuation (attenuation: how the radiation changes as goes through the body during the imaging process). Often, it is a tradeoff between the two.
Both of these parameters are a function of wavelength
We can't medical-image with visible light, since the human body is opaque to it
-How X-rays work-
Tungsten cathode: bombards tungsten target with electrons, the target is hooked up to a copper anode
X-rays produced by the electron/target collision
X-rays are 2D representation of a 3D object; thus aren't good for analyzing abnormal structures where you aren't sure what structure to expect
-Computer tomography-
Uses X-rays
Takes 2D images of a 3D volume (like the human body) - "slices" - target needs to be aligned straight with the beam generator
Several of these images, aggregated into one picture
Backprojection: Looking at the same slice of the body from different angles
-Positron emission tomography (PET)-
Proton --> Neutron + Neutrino + Positron
[Part of radioactive decay: inject radioactive agent during PET to cause this to happen]
Positron + Electron: antimatter annihilation that produces a gamma-ray signature. The latter is detected
Areas of higher metabolism (like cancer tumors) give off a stronger signature
-MRI-
This has been covered before
Hydrogen protons on particular become excited in a strong magnetic field, then turn the field off, which thus changes the signal behavior.
You image based on this.
-Ultrasound-
Useful on pregnant women because it's safe/not radioactive
Has other uses as well
We know the speed of sound in the body because know the speed of sound in water, and the body is mostly water
You image based on the ultrasound's echoes
Doppler ultrasound can image blood flow
Visible Human Project: part of NIH
Gathers data about human body parts that can be use din designing and tweaking these imaging processes
modality: a term for a different medical-imaging process
Often get complementary images from using different processes on the same object
Could look at these images side-by-side or no top of each other
Images often pseudocolored to help humans read + analyze them
Simulated/"phantom" images are often useful for gathering general information
Still useful on kidneys - would see kidney stones
Before Roentgen's X-ray discovery, no way to look at body besides cutting it open
Some medical imaging methods (like X-ray) provide a picture, some (like ultrasound) provide a real-time picture
Where in the electromagnetic spectrum do we look?
Two parameters: resolution and attenuation (attenuation: how the radiation changes as goes through the body during the imaging process). Often, it is a tradeoff between the two.
Both of these parameters are a function of wavelength
We can't medical-image with visible light, since the human body is opaque to it
-How X-rays work-
Tungsten cathode: bombards tungsten target with electrons, the target is hooked up to a copper anode
X-rays produced by the electron/target collision
X-rays are 2D representation of a 3D object; thus aren't good for analyzing abnormal structures where you aren't sure what structure to expect
-Computer tomography-
Uses X-rays
Takes 2D images of a 3D volume (like the human body) - "slices" - target needs to be aligned straight with the beam generator
Several of these images, aggregated into one picture
Backprojection: Looking at the same slice of the body from different angles
-Positron emission tomography (PET)-
Proton --> Neutron + Neutrino + Positron
[Part of radioactive decay: inject radioactive agent during PET to cause this to happen]
Positron + Electron: antimatter annihilation that produces a gamma-ray signature. The latter is detected
Areas of higher metabolism (like cancer tumors) give off a stronger signature
-MRI-
This has been covered before
Hydrogen protons on particular become excited in a strong magnetic field, then turn the field off, which thus changes the signal behavior.
You image based on this.
-Ultrasound-
Useful on pregnant women because it's safe/not radioactive
Has other uses as well
We know the speed of sound in the body because know the speed of sound in water, and the body is mostly water
You image based on the ultrasound's echoes
Doppler ultrasound can image blood flow
Visible Human Project: part of NIH
Gathers data about human body parts that can be use din designing and tweaking these imaging processes
modality: a term for a different medical-imaging process
Often get complementary images from using different processes on the same object
Could look at these images side-by-side or no top of each other
Images often pseudocolored to help humans read + analyze them
Simulated/"phantom" images are often useful for gathering general information
Wednesday, April 23, 2008
Outlines [Vision And Mind example]
This came to mind as I'm working on Topic Summary #3:
An outline is a good way to prep for doing the topic summary, but it's also a good way to think about the topic, in general.
So here goes:
-Vision And Mind-
* the physiology of the vision system
** details on structure of the eye
*** Rods & Cones
** details on the visual cortex and on V1 through V5
*** where it's located compared to the rest of the brain.
** "lateral inhibition", and how it accentuates the edges of an object
** eye movements
*** depends on the size of the object/scene to be visualized (the object/scene to be visualized is counted in degrees squared)
*** oculomotor system
*** saccades
*** various ways of tracing a moving object
** field-of-view vs. acuity conflict
-------------------------------------------------------
* the psychology of the vision system
** How can we visualize brain psychology?
by various medical-imaging techniques:
*** EEG
*** MRI vs. fMRI, differences
** How certain optical illusions work
*** really should be 'neural illusions'?
*** name a few big-name optical illusions & discuss them
----------------------------------------------------------------
* relation to other senses
** brain lobe where inputs from other senses 'meet'
** use of visual system to compensate for other sight loss
** use of other sensory systems to compensate for vision loss
An outline is a good way to prep for doing the topic summary, but it's also a good way to think about the topic, in general.
So here goes:
-Vision And Mind-
* the physiology of the vision system
** details on structure of the eye
*** Rods & Cones
** details on the visual cortex and on V1 through V5
*** where it's located compared to the rest of the brain.
** "lateral inhibition", and how it accentuates the edges of an object
** eye movements
*** depends on the size of the object/scene to be visualized (the object/scene to be visualized is counted in degrees squared)
*** oculomotor system
*** saccades
*** various ways of tracing a moving object
** field-of-view vs. acuity conflict
-------------------------------------------------------
* the psychology of the vision system
** How can we visualize brain psychology?
by various medical-imaging techniques:
*** EEG
*** MRI vs. fMRI, differences
** How certain optical illusions work
*** really should be 'neural illusions'?
*** name a few big-name optical illusions & discuss them
----------------------------------------------------------------
* relation to other senses
** brain lobe where inputs from other senses 'meet'
** use of visual system to compensate for other sight loss
** use of other sensory systems to compensate for vision loss
Halstone's electron-microscope lab
This lab uses TEMs (tunneling electron microscopes)
Can't use glass lenses to focus electron beams; have to use magnetic lenses; this *is* a tradeoff
X-ray microscopes don't have the quality we want yet, gamma-ray microscopes are still atleast a few years down the road
Mosely's law - 1914: hit something w/ electrons and produce X-rays
* Radiation issues inherent
* Depending on the energy level of the X-rays, you can tell what element emitted it
Electron gun fires a beam down the main column
Tungsten filament is excited and
200,000 volts
200,000 kilo-electron volts
Moving at ~ 1/3 the speed of light, need to use Relativity-based equations
Specimen in center of column, on the end of a handle
Whole column has to be under vacuum
One magnetic lens controls spot size of beam; there are several other lenses aswell
Objective lens nearest the bottom of the column; it's what actually produces the image.
^ How do you *see* electrons?
At bottom of column, a screen covered with zinc sulfide...Electrons put some part(s) of that into an excited state, and they flouresce green.
Green-ness caught by film
X-ray detectors chilled to liquid-nitrogen temperatures.
This can be used to analyze what elements ar ein each section of the sample
Specimens extremely small (~3mm diameter, and very thin (<200nm, even thinner for heavy elements))
What is 2,000,000x magnification? A person magnified this much would be two thousand miles tall?
What is a nanometer versus a meter? Size of a golf ball versions the size of the Earth
Electron microscopes very sensitive. Even sound waves form talking, etc. can cause the image to 'jump' a bit
Electron diffraction - electron beam scattered by hitting a crystalline structure. Depending on how they scatter, you can determine what the crystal structure is. Often a ring pattern of some sort.
Lattice planes in asbestos are 9 angstroms (.9 nm) apart
Easy to detect dead space in a crystalline structure vs. the location of the atoms themselves
--------
*Scanning electron microscope*
Shorter column
20k eV up to 30k or 40k eV
Secondary electrons kicked off by the sample itself
Can vary distance between sample and electron beam
General good microscope idea: start at low magnification to get an overview, then zoom in
A high frame rate leads to more noise "static" (spend less time scanning a particular pixel)
Low frame rate - less "noise", but takes longer to produce the image
Low voltage; less penetration; should mean more surface detail [and vice versa]
SEM useful for building a picture of where exactly atoms of element X are located throughout the sample
H, He, Li, and Be can't be detected via this X-ray detector equipment
astigmatism: vertical image in separate focus from the horizontal image
Spehrical and chromatic aberation you need different equipment to correct
---
Halstone uses a srtaightforward same (copper+aluminum disk) to calibrate the settings
---
The material you used to prepare the specimen (gold coat, etc), can screw with the view
Can't use glass lenses to focus electron beams; have to use magnetic lenses; this *is* a tradeoff
X-ray microscopes don't have the quality we want yet, gamma-ray microscopes are still atleast a few years down the road
Mosely's law - 1914: hit something w/ electrons and produce X-rays
* Radiation issues inherent
* Depending on the energy level of the X-rays, you can tell what element emitted it
Electron gun fires a beam down the main column
Tungsten filament is excited and
200,000 volts
200,000 kilo-electron volts
Moving at ~ 1/3 the speed of light, need to use Relativity-based equations
Specimen in center of column, on the end of a handle
Whole column has to be under vacuum
One magnetic lens controls spot size of beam; there are several other lenses aswell
Objective lens nearest the bottom of the column; it's what actually produces the image.
^ How do you *see* electrons?
At bottom of column, a screen covered with zinc sulfide...Electrons put some part(s) of that into an excited state, and they flouresce green.
Green-ness caught by film
X-ray detectors chilled to liquid-nitrogen temperatures.
This can be used to analyze what elements ar ein each section of the sample
Specimens extremely small (~3mm diameter, and very thin (<200nm, even thinner for heavy elements))
What is 2,000,000x magnification? A person magnified this much would be two thousand miles tall?
What is a nanometer versus a meter? Size of a golf ball versions the size of the Earth
Electron microscopes very sensitive. Even sound waves form talking, etc. can cause the image to 'jump' a bit
Electron diffraction - electron beam scattered by hitting a crystalline structure. Depending on how they scatter, you can determine what the crystal structure is. Often a ring pattern of some sort.
Lattice planes in asbestos are 9 angstroms (.9 nm) apart
Easy to detect dead space in a crystalline structure vs. the location of the atoms themselves
--------
*Scanning electron microscope*
Shorter column
20k eV up to 30k or 40k eV
Secondary electrons kicked off by the sample itself
Can vary distance between sample and electron beam
General good microscope idea: start at low magnification to get an overview, then zoom in
A high frame rate leads to more noise "static" (spend less time scanning a particular pixel)
Low frame rate - less "noise", but takes longer to produce the image
Low voltage; less penetration; should mean more surface detail [and vice versa]
SEM useful for building a picture of where exactly atoms of element X are located throughout the sample
H, He, Li, and Be can't be detected via this X-ray detector equipment
astigmatism: vertical image in separate focus from the horizontal image
Spehrical and chromatic aberation you need different equipment to correct
---
Halstone uses a srtaightforward same (copper+aluminum disk) to calibrate the settings
---
The material you used to prepare the specimen (gold coat, etc), can screw with the view
Monday, April 21, 2008
How do they work?
Okay, how do these types of medical imaging work?
* Ultrasound
How it works: Bombardment of sound waves above 20,000 hertz (20khZ), 20khz being the upper limit of human hearing
What is actually measured: Ultrasound actually measures the echoes received by the ultrasound machine after they bounce back from hitting body parts.
An electrical pulse transducer in the machine causes it to vibrate at a certain frequency. Likewise, the echoes cause the transducer to vibrate in various ways, converted into electrical pulses which are then converted into a digital image
Advantages: Light if any side effects, very good at imaging soft tissue (vary frequency for different kinds of soft tissue), can produce a "live video" feed during the procedure
* fMRI (Functional Magnetic Resonance Imaging)
How it works: Images the brain and brain activity, though the method would technically work on other areas of the body
What is actually measured: It does this by detecting the increased blood flow typically associated with neural activity
How does it act as a proxy: Neural activity kicks up blood flow, with the areas of increased blood flow being measured
* SPECT
How it works: Radioisotopes fed into body, and the gamma rays are detected by the SPECT equipment
What is actually measured: The rays received by the machine are measured as 2-D images, but are measured form different angles, enabling a 3D image to be produced
How does it act as a proxy?: See info about 3-D reconstruction method above. Also, the radio decay particles behave differently when passing through different body structures, hence the ability for this to measure anything at all
* electromicroscopy
How it works: Magnifies samples to a much higher degree of resolution than is possible with a light microscope.
What is actually measured: Very small/thin sample bombarded with an electron beam. As electrons go through the object (in tunneling electron microscopy, or TEM), they are recorded as how they were 'behaving' as they come out
How does it act as a proxy?: Impediments inside the sample modify the outgoing electron beam.
* Ultrasound
How it works: Bombardment of sound waves above 20,000 hertz (20khZ), 20khz being the upper limit of human hearing
What is actually measured: Ultrasound actually measures the echoes received by the ultrasound machine after they bounce back from hitting body parts.
An electrical pulse transducer in the machine causes it to vibrate at a certain frequency. Likewise, the echoes cause the transducer to vibrate in various ways, converted into electrical pulses which are then converted into a digital image
Advantages: Light if any side effects, very good at imaging soft tissue (vary frequency for different kinds of soft tissue), can produce a "live video" feed during the procedure
* fMRI (Functional Magnetic Resonance Imaging)
How it works: Images the brain and brain activity, though the method would technically work on other areas of the body
What is actually measured: It does this by detecting the increased blood flow typically associated with neural activity
How does it act as a proxy: Neural activity kicks up blood flow, with the areas of increased blood flow being measured
* SPECT
How it works: Radioisotopes fed into body, and the gamma rays are detected by the SPECT equipment
What is actually measured: The rays received by the machine are measured as 2-D images, but are measured form different angles, enabling a 3D image to be produced
How does it act as a proxy?: See info about 3-D reconstruction method above. Also, the radio decay particles behave differently when passing through different body structures, hence the ability for this to measure anything at all
* electromicroscopy
How it works: Magnifies samples to a much higher degree of resolution than is possible with a light microscope.
What is actually measured: Very small/thin sample bombarded with an electron beam. As electrons go through the object (in tunneling electron microscopy, or TEM), they are recorded as how they were 'behaving' as they come out
How does it act as a proxy?: Impediments inside the sample modify the outgoing electron beam.
Types of Medical Imaging
We'll be investigating some forms of medical imaging in class on Wed. (4/25) and Fri. (4/25)
Now what are the different types of medical imaging?
-Things that analyze brain waves, even though they aren't imaging something visible, are still a form of medical imaging-
* such as electroencephalography (EEG)
Many techniques exist that take images of physical body parts...
* X-rays (Classic!)
* Magnetic resonance imaging (MRI) + fMRI
* Positron emission tomography (PET)
* Computerized tomography (CAT)
* Ultrasound
--
endoscopy
* SPECT
* radioisotope-based techniques: nuclear medicine + flouroscopy
* thermography
* electron microscopy
* Raman spectroscopy
* image guided biopsy
* angiography
Now what are the different types of medical imaging?
-Things that analyze brain waves, even though they aren't imaging something visible, are still a form of medical imaging-
* such as electroencephalography (EEG)
Many techniques exist that take images of physical body parts...
* X-rays (Classic!)
* Magnetic resonance imaging (MRI) + fMRI
* Positron emission tomography (PET)
* Computerized tomography (CAT)
* Ultrasound
--
endoscopy
* SPECT
* radioisotope-based techniques: nuclear medicine + flouroscopy
* thermography
* electron microscopy
* Raman spectroscopy
* image guided biopsy
* angiography
Friday, April 18, 2008
Electron Microscopy
Electron MIcroscopes come in two forms: The Tunneling Electron Microscope (TEM) and the Scanning Electron Microscope (SEM).
What is the difference? Both use beams of electrons.
However, the difference resides in the fact that the different types of machines direct the electron beam differently.
Tunneling Electron Microscopes send an electron beam *through* the object. This means theta they are good at gathering details on the inside of the object (which is especially important with cells), and of the surface of small objects.
Scanning Electorn Microscopes send their electron beams along the outside of objects. They are most effective for analyzing the surface of large/thick objects
The STEM (Scanning transmission electron microscope) combines some of the advantageous features of each, logically enough.
There are online simulators, based on Flash, Java, or the like, that give you an impression of how an electron microscope works. By adjusting settings common to an electorn microscope, and chosing from a premade set of 'samples', you see the resultant image.
http://micro.magnet.fsu.edu/primer/java/electronmicroscopy/magnify1/index.html is an example
What is the difference? Both use beams of electrons.
However, the difference resides in the fact that the different types of machines direct the electron beam differently.
Tunneling Electron Microscopes send an electron beam *through* the object. This means theta they are good at gathering details on the inside of the object (which is especially important with cells), and of the surface of small objects.
Scanning Electorn Microscopes send their electron beams along the outside of objects. They are most effective for analyzing the surface of large/thick objects
The STEM (Scanning transmission electron microscope) combines some of the advantageous features of each, logically enough.
There are online simulators, based on Flash, Java, or the like, that give you an impression of how an electron microscope works. By adjusting settings common to an electorn microscope, and chosing from a premade set of 'samples', you see the resultant image.
http://micro.magnet.fsu.edu/primer/java/electronmicroscopy/magnify1/index.html is an example
Wednesday, April 9, 2008
Questions answered by Andy & Jeff
TMS = transcranial magnetic stimulation
Blinded or blindfolded people - this frees up processing capacity in the visual cortex, some of which is used for other types of sensory processing
In deaf people, the auditory cortex probably does something
Same parts of brain for thinking about something, and perceiving it. So thinking about something during a dream may helpyou perceive it when you're awake
During sleep, the memory-forming hippocampus is more-active
Sleep is mental regeneration (see above), as well as physical regeneration
Cramming - does not work for long-term retention
Eye -->LGN --> V1 --> V2 --> V3 --> V4 --> V5
Not always a linear pathway, there are some connections that skip/go backwards in this chain.
The different V's process somewhat different types of signals (have different capacities), but these roles are interconencted. (Removing V4 doesn't
LGN - laterogenetic nucleus of the thalamus
Allan Cowe - vision experiments on monkeys
The brain is to some extent a dynamic self-repairing system
At a certain point, the things [experiments] we want to do are illegal or unethical - Andy Herbert
Don't overdo the computer analogies here in brain psychology
SOme optical illusions are the result of the brain taking necessary processing shortcuts
"Is what we see really there?" - That gets into philosophy
Integrating the senses is important - Sense A compensates for a weakness of Sense B
Normally, the senses paint a complementary picture...very disorienting when they don't
Contrast sensitivity - vision of shadows vs. vision of discrete objects
Different among different species, because different species need visions systems adapted to their different environment
Can see what capacity is missing when a certain section of the brain is gone.
First started relazing this en masse with Civil War musketball-to-the-head injuries
Cortex has higher-order roles than things like the thalamus. Things liek the thalamus handle basic body functions for the most part.
Drugs,and not just the funky illegal ones - have effect on neurotrasmitters.
Range of visual sensitivity amongst normal humans
This may explain how a lot of drugs produce haalucinations and the like
Blinded or blindfolded people - this frees up processing capacity in the visual cortex, some of which is used for other types of sensory processing
In deaf people, the auditory cortex probably does something
Same parts of brain for thinking about something, and perceiving it. So thinking about something during a dream may helpyou perceive it when you're awake
During sleep, the memory-forming hippocampus is more-active
Sleep is mental regeneration (see above), as well as physical regeneration
Cramming - does not work for long-term retention
Eye -->LGN --> V1 --> V2 --> V3 --> V4 --> V5
Not always a linear pathway, there are some connections that skip/go backwards in this chain.
The different V's process somewhat different types of signals (have different capacities), but these roles are interconencted. (Removing V4 doesn't
LGN - laterogenetic nucleus of the thalamus
Allan Cowe - vision experiments on monkeys
The brain is to some extent a dynamic self-repairing system
At a certain point, the things [experiments] we want to do are illegal or unethical - Andy Herbert
Don't overdo the computer analogies here in brain psychology
SOme optical illusions are the result of the brain taking necessary processing shortcuts
"Is what we see really there?" - That gets into philosophy
Integrating the senses is important - Sense A compensates for a weakness of Sense B
Normally, the senses paint a complementary picture...very disorienting when they don't
Contrast sensitivity - vision of shadows vs. vision of discrete objects
Different among different species, because different species need visions systems adapted to their different environment
Can see what capacity is missing when a certain section of the brain is gone.
First started relazing this en masse with Civil War musketball-to-the-head injuries
Cortex has higher-order roles than things like the thalamus. Things liek the thalamus handle basic body functions for the most part.
Drugs,and not just the funky illegal ones - have effect on neurotrasmitters.
Range of visual sensitivity amongst normal humans
This may explain how a lot of drugs produce haalucinations and the like
Friday, April 4, 2008
(4/4/08) Answers to Thought-Provoking Questions
Why do some stars turn into black holes?
Stars that were massive enough turn into black holes when they die.
A dead star doesn't have enough fuel to keep fusion going.
The fusion reaction produces energy and heat that counterbalances the gravitational pull of the star on itself
This is called "hydrostatic equilibrium"
Objects in a system orbit around the center of mass
Galaxies in a cluster kind of orbit each other rather than expanding and spreading out the way the Hubble pattern would predict. SO they become more inclined to collide.
What keeps smaller object in orbit, rather than falling towards the central mass?
* the energy of the small object itself
* orbit is at a point where energy of object balances the energy of gravitational pull
gravitational tides between galaxies can affect orbits if the galaxies are close enough
During a galactic collision, you're likely to have more material falling into a black hole
Time travel very speculative - all of the discussion is theoretical at this point. Some ways time travel might happen:
*Faster-than-light (back in time)
*Travel through wormhole w/o getting destroyed
* Go to similar parallel universe
* Are parallel universes preexisting, or created by the act of time travel
* If parallel universes exist, there would probably be an infinite amount of them, for each branching-off point. If there was a limited amount,how would it be chosen?
* Parallel universmany not just have different history, but different laws of physics
Standard candle - a group of objects with the same brightness.
Different form units of measure such as "solar luminosity"
Standard rod -similar concept with shape
In astronomy, can measure apparent brightness and apparent size.
apparent brightness, apparent size, actual size, actual brightness and distance - if you knoow some fo these, you can figure out the rest
"Do black holes ever go away?"
The massive ones are around forever,the smaller ones are likely to disappear
The Drake Equation - equation that takes several factors; determines the probability of intelligent life; however, you have to make assumptions
Stars that were massive enough turn into black holes when they die.
A dead star doesn't have enough fuel to keep fusion going.
The fusion reaction produces energy and heat that counterbalances the gravitational pull of the star on itself
This is called "hydrostatic equilibrium"
Objects in a system orbit around the center of mass
Galaxies in a cluster kind of orbit each other rather than expanding and spreading out the way the Hubble pattern would predict. SO they become more inclined to collide.
What keeps smaller object in orbit, rather than falling towards the central mass?
* the energy of the small object itself
* orbit is at a point where energy of object balances the energy of gravitational pull
gravitational tides between galaxies can affect orbits if the galaxies are close enough
During a galactic collision, you're likely to have more material falling into a black hole
Time travel very speculative - all of the discussion is theoretical at this point. Some ways time travel might happen:
*Faster-than-light (back in time)
*Travel through wormhole w/o getting destroyed
* Go to similar parallel universe
* Are parallel universes preexisting, or created by the act of time travel
* If parallel universes exist, there would probably be an infinite amount of them, for each branching-off point. If there was a limited amount,how would it be chosen?
* Parallel universmany not just have different history, but different laws of physics
Standard candle - a group of objects with the same brightness.
Different form units of measure such as "solar luminosity"
Standard rod -similar concept with shape
In astronomy, can measure apparent brightness and apparent size.
apparent brightness, apparent size, actual size, actual brightness and distance - if you knoow some fo these, you can figure out the rest
"Do black holes ever go away?"
The massive ones are around forever,the smaller ones are likely to disappear
The Drake Equation - equation that takes several factors; determines the probability of intelligent life; however, you have to make assumptions
Wednesday, April 2, 2008
E = mc^2
E = mc^2 actually refers to particles without motion, plus the energy of motion
With the energy of motion, you can have mass of 0, and still have energy
Applies to many different areas of the universe
E = mc^2: A recipe for converting matter to energy and vice versa - requires energy to make such a conversion, and a lot of energy
Energy doesn't take up much space, takes up more space when converted into matter
With the energy of motion, you can have mass of 0, and still have energy
Applies to many different areas of the universe
E = mc^2: A recipe for converting matter to energy and vice versa - requires energy to make such a conversion, and a lot of energy
Energy doesn't take up much space, takes up more space when converted into matter
(4/2/08) - From Big Bang to Black Holes
Most of what we know about the universe comes from our analysis of electromagnetic radiation (i.e. light)
Light is like a wave
Electronic wave and magnetic wave oscillate together
Black hole in center of galaxy = 1 million times the mass of the sun
The Sun = a basic unit of measurement
ergs = g*cm^2 / second^2
Solar luminosity = 3.8 * 10^33 ergs/s
Mass: 2 * 10^30 kg
Age of universe: 13.7 billion years
Speed of light = 3 * 10^8 m/s
parsec = 3.26 light years
Special Relativity
2 main components:
* The laws of physics ar ehte same in any inertial frame
* The speed of light is the same for all observers in an inertial frame
Spacetime is 4-dimensional
A frame in which unaccelerated objects move in straight lines is an inertial frame
A globally inertial frame is a frame that covers all spacetime
Addition of speeds
Walking 5 mph, Bus 30mph, difference 25mph
Rocket 100,000km/s, Light 300,000km/s
Difference appears differently because the observers involved see spacetime differently
Time dilation: the time lapse between 2 events changes from one observer to another; it is dependent on the relative speed of the observers
Lorentz contraction - the dimensions of an object as measured by one observer may be smaller than that of another observer
This also has implications for how gravity works
Newtonian gravity: F = G (m1 m2)/r^2
General Relativity: mass-energy causes spacetime to curve
Objects, including light, follow the shortest path in curved spacetime
Gravity = curvature of spacetime
Clocks more slowly the closer they are to a gravitational mass
Sun's gravity would bend light coming from background stars
Time slows near any massive body. Slows down even near Earth. [albeit in very small amounts - 4 parts in 10 billion]
The angular momentum of a rotating body drags space into a tornado-like whirl around it. (small whirl
Will see object differently if a mass is on the way. This is called a "gravitational lens".
When the gravitational lens is perfectly aligned with the background object, the background object is modified into an Einstein Ring
Black holes - so much mass in such a small space that the spacetime warp is extreme
Nothing can escape, not even light
Detect black holes by their gravitational effect on nearby object
Stars, specially those near Galactic Center, are detected orbiting it
Supermassive black holes probably exist at the centers of most galaxies
Called galactic nuclei
Could have come about or become larger during galactic mergers
Collision of two black holes is the most violent event in the universe
* Produces wild vibrations of warped spacetime
Black holes related to their host galaxies: "chicken & egg" problem
* galaxy formation far enough back in time that we can't really tell
* Hypothesis: growing together
What happens in a black hole, stays on a black hole. This is how black holes build mass.
Light is like a wave
Electronic wave and magnetic wave oscillate together
Black hole in center of galaxy = 1 million times the mass of the sun
The Sun = a basic unit of measurement
ergs = g*cm^2 / second^2
Solar luminosity = 3.8 * 10^33 ergs/s
Mass: 2 * 10^30 kg
Age of universe: 13.7 billion years
Speed of light = 3 * 10^8 m/s
parsec = 3.26 light years
Special Relativity
2 main components:
* The laws of physics ar ehte same in any inertial frame
* The speed of light is the same for all observers in an inertial frame
Spacetime is 4-dimensional
A frame in which unaccelerated objects move in straight lines is an inertial frame
A globally inertial frame is a frame that covers all spacetime
Addition of speeds
Walking 5 mph, Bus 30mph, difference 25mph
Rocket 100,000km/s, Light 300,000km/s
Difference appears differently because the observers involved see spacetime differently
Time dilation: the time lapse between 2 events changes from one observer to another; it is dependent on the relative speed of the observers
Lorentz contraction - the dimensions of an object as measured by one observer may be smaller than that of another observer
This also has implications for how gravity works
Newtonian gravity: F = G (m1 m2)/r^2
General Relativity: mass-energy causes spacetime to curve
Objects, including light, follow the shortest path in curved spacetime
Gravity = curvature of spacetime
Clocks more slowly the closer they are to a gravitational mass
Sun's gravity would bend light coming from background stars
Time slows near any massive body. Slows down even near Earth. [albeit in very small amounts - 4 parts in 10 billion]
The angular momentum of a rotating body drags space into a tornado-like whirl around it. (small whirl
Will see object differently if a mass is on the way. This is called a "gravitational lens".
When the gravitational lens is perfectly aligned with the background object, the background object is modified into an Einstein Ring
Black holes - so much mass in such a small space that the spacetime warp is extreme
Nothing can escape, not even light
Detect black holes by their gravitational effect on nearby object
Stars, specially those near Galactic Center, are detected orbiting it
Supermassive black holes probably exist at the centers of most galaxies
Called galactic nuclei
Could have come about or become larger during galactic mergers
Collision of two black holes is the most violent event in the universe
* Produces wild vibrations of warped spacetime
Black holes related to their host galaxies: "chicken & egg" problem
* galaxy formation far enough back in time that we can't really tell
* Hypothesis: growing together
What happens in a black hole, stays on a black hole. This is how black holes build mass.
Monday, March 31, 2008
(3/31/08) From Big Bang to Black Holes: Part II
The Big Bang
The Evolution of the Universe
Galaxy Formation and Evolution
Dark Matter/Dark Energy
The Big Questions
Future Prospects
--
-Basic Forces-
Strong nuclear force - Holds nuclei together: Strength 1, Range 10^-15 m, gluons + nucleons
Electromagnetic Force - Strength 1/137, Range Infinite, photon [mass o] [ spin 1]
Weak - Strength 10^-6, range 10^-18m [0.1% of the diameter of a proton], intermediate vector bosons, W+, W-, Z0,mass > 80 GeV, spin =1
Gravity - Strength 6 * 10^-39, Range Infinite, [potential gravitron particle], mass =0, spin = 2
Cosmological principle - isotropic [large-scale structure looks the same in all directions] and homogenous [general physical properties are the same everywhere]
The universe has no edge and no center
-Hubble Law-
On large scales, galaxies are moving apart, with velocity proportional to distance
There is no center of expansion
Spacetime itself is expanding and carrying the galaxies with it
^ Can tell this via cosmological redshift
Redshift = (wavelength - original wavelngth) / (original wavelength)
Extrapolating backwards w/ Hubble's Law = universe had a beginning [infinitely small and hot] - the cosmic singularity
(Planck's constant t = 1.35*(10^-43) sec
--
We should expect thermal radiation from hot gas
Radiation should is blackbody spectrum
Initially, all four forces were equally strong.
Broke off in the following order: gravity, strong force, weak force
Gravity broke off (forze out) within 1 Planck time of Big Bang
First Galaxies - Approx. 1billion years after Big Bang
Bizarre inflationary period - exponential expansion of universe soon after Big Bang
W/O inflationary period, universe would have had to start out relatively large
Infationary period theory - explains lack of magnetic monopoles, horizon problem, flatness problem
Horizon problem: things far enough apart that they didn't come into contact with each other
Flatness problem: near critical energy density (eqiuilibrium point between infinite expansion and infinite compression) - Sphere needed to move from a small size (high arc) to large size (low arc) quickly
Initially, was equilibrium between pair production and annihilation (between regular matter and antimatter). There was a slight shift in favor of regular matter
Then, atomic nuclei were created (a few seconds after the Big Bang). This settled out a few minutes after the Big Bang.
This initial process created hydrogen, helium, lithium and beryllium (along with hydrogen isotope deuterium). Mostly hydrogen/helium.
Other elements were formed via fusion in the center of stars.
As universe expanded, it cooled down, cooled down to a point where atoms formed, and electrons were not allowed to interfere with photons anymore, because they were locked down in atoms
Cosmic Background Radiation was predicted as a 'signature' of the Big Bang.
R. Wilson and A. Penzias won the Nobel Prize for discovering this in 1978
Highly isotropic - intensity of this radiation very similar in all directions
Perfect blackbody spectrum would have a temperature of 2.725 Kelvin
Slight nonuniformity explains the clusters of matter that ended up as galaxies
Spiral galaxies: relatively small nuclear bulge, disk with spiral arms, gas/dust/star formation/young stars
Barred spirals are 2/3 of all spirals; they have elongated nuclei with spiral arms emerging from the ends
Elliptical galaxies: squashed-sphere shape, largely old stars
---
Even seemingly empty patches of sky probably contain very distant, faint galaxies
Most galaxies are members of clusters; galaxy clusters themselves are grouped into superclusters [many superclusters have a few dozen clusters spread out over ~40 Mpc]
Superclusters are *not* gravitationally bound
Rich Clusters - >1000 galaxies, ~ 3Mpc diameter, condensed around a giant central galaxy
Poor Clusters - 10-1000 galaxies, more spirals
Isolated galaxies are mostly spirals
Hierarchichal merging - start of cloud og gas, which starts telling out and clumping into discrete entities.
Galaxies were formed this way, and probably solar systems aswell
Star birth comes about relatively early in the universe (0.5 - 1.0 billion years ago)
Dark Energy - 70% of universe
Dark Matter - 25% of universe
Free H, He - 4%
Stars - .5%
Neutrinos - .3%
Heavy Elements - .03%
By the way gravity is behaving, we know there has to be a certain amount of mass, not all of which is visible matter - hence, dark matter
Is dark matter baryonicor nonbaryonic? Most probably nonbaryonic
Gravity should slow down expansion, dark energy should speed up expansion
Current data pointing to expansionary model; we're not sure.
The Evolution of the Universe
Galaxy Formation and Evolution
Dark Matter/Dark Energy
The Big Questions
Future Prospects
--
-Basic Forces-
Strong nuclear force - Holds nuclei together: Strength 1, Range 10^-15 m, gluons + nucleons
Electromagnetic Force - Strength 1/137, Range Infinite, photon [mass o] [ spin 1]
Weak - Strength 10^-6, range 10^-18m [0.1% of the diameter of a proton], intermediate vector bosons, W+, W-, Z0,mass > 80 GeV, spin =1
Gravity - Strength 6 * 10^-39, Range Infinite, [potential gravitron particle], mass =0, spin = 2
Cosmological principle - isotropic [large-scale structure looks the same in all directions] and homogenous [general physical properties are the same everywhere]
The universe has no edge and no center
-Hubble Law-
On large scales, galaxies are moving apart, with velocity proportional to distance
There is no center of expansion
Spacetime itself is expanding and carrying the galaxies with it
^ Can tell this via cosmological redshift
Redshift = (wavelength - original wavelngth) / (original wavelength)
Extrapolating backwards w/ Hubble's Law = universe had a beginning [infinitely small and hot] - the cosmic singularity
(Planck's constant t = 1.35*(10^-43) sec
--
We should expect thermal radiation from hot gas
Radiation should is blackbody spectrum
Initially, all four forces were equally strong.
Broke off in the following order: gravity, strong force, weak force
Gravity broke off (forze out) within 1 Planck time of Big Bang
First Galaxies - Approx. 1billion years after Big Bang
Bizarre inflationary period - exponential expansion of universe soon after Big Bang
W/O inflationary period, universe would have had to start out relatively large
Infationary period theory - explains lack of magnetic monopoles, horizon problem, flatness problem
Horizon problem: things far enough apart that they didn't come into contact with each other
Flatness problem: near critical energy density (eqiuilibrium point between infinite expansion and infinite compression) - Sphere needed to move from a small size (high arc) to large size (low arc) quickly
Initially, was equilibrium between pair production and annihilation (between regular matter and antimatter). There was a slight shift in favor of regular matter
Then, atomic nuclei were created (a few seconds after the Big Bang). This settled out a few minutes after the Big Bang.
This initial process created hydrogen, helium, lithium and beryllium (along with hydrogen isotope deuterium). Mostly hydrogen/helium.
Other elements were formed via fusion in the center of stars.
As universe expanded, it cooled down, cooled down to a point where atoms formed, and electrons were not allowed to interfere with photons anymore, because they were locked down in atoms
Cosmic Background Radiation was predicted as a 'signature' of the Big Bang.
R. Wilson and A. Penzias won the Nobel Prize for discovering this in 1978
Highly isotropic - intensity of this radiation very similar in all directions
Perfect blackbody spectrum would have a temperature of 2.725 Kelvin
Slight nonuniformity explains the clusters of matter that ended up as galaxies
Spiral galaxies: relatively small nuclear bulge, disk with spiral arms, gas/dust/star formation/young stars
Barred spirals are 2/3 of all spirals; they have elongated nuclei with spiral arms emerging from the ends
Elliptical galaxies: squashed-sphere shape, largely old stars
---
Even seemingly empty patches of sky probably contain very distant, faint galaxies
Most galaxies are members of clusters; galaxy clusters themselves are grouped into superclusters [many superclusters have a few dozen clusters spread out over ~40 Mpc]
Superclusters are *not* gravitationally bound
Rich Clusters - >1000 galaxies, ~ 3Mpc diameter, condensed around a giant central galaxy
Poor Clusters - 10-1000 galaxies, more spirals
Isolated galaxies are mostly spirals
Hierarchichal merging - start of cloud og gas, which starts telling out and clumping into discrete entities.
Galaxies were formed this way, and probably solar systems aswell
Star birth comes about relatively early in the universe (0.5 - 1.0 billion years ago)
Dark Energy - 70% of universe
Dark Matter - 25% of universe
Free H, He - 4%
Stars - .5%
Neutrinos - .3%
Heavy Elements - .03%
By the way gravity is behaving, we know there has to be a certain amount of mass, not all of which is visible matter - hence, dark matter
Is dark matter baryonicor nonbaryonic? Most probably nonbaryonic
Gravity should slow down expansion, dark energy should speed up expansion
Current data pointing to expansionary model; we're not sure.
Friday, March 28, 2008
Topic Summaries
Topic summaries are a major part of this class' assignment mix.
They consist, of, well, a summary of each topic the class covered. (There are four separate documents involved; one for each of the four topics)
We're given latitude in what format to use.
Common is the old standby; PowerPoint (However, this has to be done well; not just simple bulleted text and the like)
Our classroom has some special equipment that can be summed up as a 'immersive environment'. A large part of this is a wide special screen, which actually seems to consist of four panels. Easier to see, and with the capability of displaying more information at a time. One of the things it can do is display four slides' worth of information at a time, and I am using for my topic summary a Power Point template designed to work with this feature.
They consist, of, well, a summary of each topic the class covered. (There are four separate documents involved; one for each of the four topics)
We're given latitude in what format to use.
Common is the old standby; PowerPoint (However, this has to be done well; not just simple bulleted text and the like)
Our classroom has some special equipment that can be summed up as a 'immersive environment'. A large part of this is a wide special screen, which actually seems to consist of four panels. Easier to see, and with the capability of displaying more information at a time. One of the things it can do is display four slides' worth of information at a time, and I am using for my topic summary a Power Point template designed to work with this feature.
Tags
Tags
The Frontiers of Science class covers 4 topics: Viruses, NanoPower, Vision and the Mind, and Big Bang/Black Holes
Blogger's tag system is an excellent way to sort out which posts go with which topics:
http://alan-labbook.blogspot.com/search/label/Viruses
http://alan-labbook.blogspot.com/search/label/NanoPower
http://alan-labbook.blogspot.com/search/label/VisionAndMind
http://alan-labbook.blogspot.com/search/label/BBBH
http://alan-labbook.blogspot.com/search/label/Administrative
http://alan-labbook.blogspot.com/search/label/General
The Frontiers of Science class covers 4 topics: Viruses, NanoPower, Vision and the Mind, and Big Bang/Black Holes
Blogger's tag system is an excellent way to sort out which posts go with which topics:
http://alan-labbook.blogspot.com/search/label/Viruses
http://alan-labbook.blogspot.com/search/label/NanoPower
http://alan-labbook.blogspot.com/search/label/VisionAndMind
http://alan-labbook.blogspot.com/search/label/BBBH
http://alan-labbook.blogspot.com/search/label/Administrative
http://alan-labbook.blogspot.com/search/label/General
Wednesday, March 26, 2008
Brain sections:
Frontal lobe: infront
Parietal lobe: behind the frontal lobe
Temporal lobe: bottom (has to do with the word 'temple', not 'time')
Occipital lobe: at the back and underside; the vision center
Temporal lobe: wraps around amyglada and hippocampus
Corpus collosum: a collection of wires that helps integration of left and right hemishperes
Occipital lobe "breaks down" into area that handle different visual functions
V1= Striped cortex = primary visual cortex = Area 17
A progression from V1 to V2, etc; but some signals skip a few laters
The five basic senses "hub" in the parietal lobe
Olfactory bulb: brain component in front center of brain, goes right to center of brain on its own sensory pathway
flavor = taste + smell
-Structure of a nerve cell-
Soma (neuron cell body) sprouting dendrites that connect to other nerve cells: 5000-10000 conenctions
Axon inside myelin sheath (myelin sheath is white; hence 'white matter'); signal travels down that axon to 'terminal buttons', the 'terminal buttons' conencting to other neurons
Small voltagde differences (70 millivolts) accumulate across the dendrites. Huge depolarization causes a neuroncharge to fire
Elctrodes can be placed directly in brain; but it's a last-ditch process.
Electrodes outisde/on the skin a different story
epileptic focus often in parietal-temporal-occipetal junction
Electrode cap - 20 electrodes: A1 and A2 (on the ears are a reference point compared to the brain activity at other points
EEG's produce a waveform patter that's different depending on the activity in question, and whether part(s) of the brian are damaged
EEGs look over seconds' worth of data
fMRI's look over minutes' worth of data
ERPs - event-related-potential [EEG-measured stimulus response
Sigt experiments: measuring responses to being told to look through certian things. Can sput a certian feature within milliseconds.
80-100ms for signal to go from eye to visual cortex
CAT scan - digitized X-ray
MRI studies brain anatomy - an MRI system would image whatever's put in
fMRIs study brain function
The whopping strength of the MRI magnet makes safety essential. Things fly - even big things. :)
Similar visual equipment in other hemishpere
Actual gray matter is 2 millimeters thick, 6 layers, 1 at outside, 6 at bottom. 3 and 4 are I/O layers, others focus on internal processing
up/down and left/right are reversed in the brain.
Frontal lobe: infront
Parietal lobe: behind the frontal lobe
Temporal lobe: bottom (has to do with the word 'temple', not 'time')
Occipital lobe: at the back and underside; the vision center
Temporal lobe: wraps around amyglada and hippocampus
Corpus collosum: a collection of wires that helps integration of left and right hemishperes
Occipital lobe "breaks down" into area that handle different visual functions
V1= Striped cortex = primary visual cortex = Area 17
A progression from V1 to V2, etc; but some signals skip a few laters
The five basic senses "hub" in the parietal lobe
Olfactory bulb: brain component in front center of brain, goes right to center of brain on its own sensory pathway
flavor = taste + smell
-Structure of a nerve cell-
Soma (neuron cell body) sprouting dendrites that connect to other nerve cells: 5000-10000 conenctions
Axon inside myelin sheath (myelin sheath is white; hence 'white matter'); signal travels down that axon to 'terminal buttons', the 'terminal buttons' conencting to other neurons
Small voltagde differences (70 millivolts) accumulate across the dendrites. Huge depolarization causes a neuroncharge to fire
Elctrodes can be placed directly in brain; but it's a last-ditch process.
Electrodes outisde/on the skin a different story
epileptic focus often in parietal-temporal-occipetal junction
Electrode cap - 20 electrodes: A1 and A2 (on the ears are a reference point compared to the brain activity at other points
EEG's produce a waveform patter that's different depending on the activity in question, and whether part(s) of the brian are damaged
EEGs look over seconds' worth of data
fMRI's look over minutes' worth of data
ERPs - event-related-potential [EEG-measured stimulus response
Sigt experiments: measuring responses to being told to look through certian things. Can sput a certian feature within milliseconds.
80-100ms for signal to go from eye to visual cortex
CAT scan - digitized X-ray
MRI studies brain anatomy - an MRI system would image whatever's put in
fMRIs study brain function
The whopping strength of the MRI magnet makes safety essential. Things fly - even big things. :)
Similar visual equipment in other hemishpere
Actual gray matter is 2 millimeters thick, 6 layers, 1 at outside, 6 at bottom. 3 and 4 are I/O layers, others focus on internal processing
up/down and left/right are reversed in the brain.
Monday, March 24, 2008
Vision and the Mind
* Imaging Science / Psychology crossover
* Professor Pelz: The role of eye movement - active vision
* "Optical illusions" really "neural illusions"
* Some illusions easy to explain; some aren't
* Very young children see some of these illusions differently; older people have visual experience
* After 20-second video of spiral, you see the spiral's movement pattern even after it's turned off. So, even for a short timeframe, your eye was 'trained' to that movement.
"Rods" and "cones" light0sensitive things in back of retina named for their shapes
"Bipolar cells" feed signal into "ganglion cells", which in turn send the signal to the optic nerve.
Light actually flows through the ganglion and bipolar cells, hits the rods and cones, and then bounces back
Photon absorbed by rod or cone; voltage induced; signal gets changed at the synapse (lateral inhibition: one full-strength positione charge, two half-strength negative charges
Sometimes neurotransmitters are struck by multiple such charges
.
If the input field is 100% uniform, the charges would entirely cancel each other out. However, at edges of objects, the strength of incoming light is different, so only the edges of the visualized object are accentuated.
This is a data-compression scheme; computer image-compression algorithms actually do something similar.
Your visual system
Herman's Grid - black squares, thick white gridlines
Criak-Obrien/Cornsweet illusion - rectangle that appears to have dark gray left half and light gray right half; really a uniform color
Fourier transform: math algorithm that looks for "just the edges"
Blurry image: has no clear edges
Snakes illusion- apparent motion when going from the spiral pattern to a blank surface.
When surface is darker, your optic system integrates the images slower, so you'll see elss flicker on a darker screen
Vertical angle * horizontal angle = degrees-squared on the field of vision
Visual system focuses on detecting motion
Field-of-view vs. acuity compromise
Cones: High acuity [and color vision]
Rods: Low acuity and high sensitivity
If you hold a finger out at arm's length, the fingernail is about 1 degree wide.
There is a blind spot at a certain degree of the field that comes form the space where the optic nerve comes back out
Small blind spot aswell form the following: No rods directly ahead (0 degrees); only cones in that area
little depression at the center of your retina
Limiting acuity in the periphery is a part of the compromise; but need to move the eye around so that the strong-acuity area can cover different parts of the world
Ocular motor system: six muscles in three pairs (one does left-right, one pair does up-down, and one does rotation)
How much info is enough?
How quick is "just in time"?
saccades = rapid movement of eyes to look at a new object or region
Smooth Pursiut: stabilizes view of a moving object
Tremor, drift and microsaccades when you try to hold your eye steady
optokinetic response / optokinetic nystagmus
Have to serialize your visual-information intake
That presents problem of temporal-integration
Various devices to track eye movement in the laboratory
* Measuring reflection off the eye, in some way, is a common method
* Wearable eye tracker is the next development goal; starting to have success on that
* Imaging Science / Psychology crossover
* Professor Pelz: The role of eye movement - active vision
* "Optical illusions" really "neural illusions"
* Some illusions easy to explain; some aren't
* Very young children see some of these illusions differently; older people have visual experience
* After 20-second video of spiral, you see the spiral's movement pattern even after it's turned off. So, even for a short timeframe, your eye was 'trained' to that movement.
"Rods" and "cones" light0sensitive things in back of retina named for their shapes
"Bipolar cells" feed signal into "ganglion cells", which in turn send the signal to the optic nerve.
Light actually flows through the ganglion and bipolar cells, hits the rods and cones, and then bounces back
Photon absorbed by rod or cone; voltage induced; signal gets changed at the synapse (lateral inhibition: one full-strength positione charge, two half-strength negative charges
Sometimes neurotransmitters are struck by multiple such charges
.
If the input field is 100% uniform, the charges would entirely cancel each other out. However, at edges of objects, the strength of incoming light is different, so only the edges of the visualized object are accentuated.
This is a data-compression scheme; computer image-compression algorithms actually do something similar.
Your visual system
Herman's Grid - black squares, thick white gridlines
Criak-Obrien/Cornsweet illusion - rectangle that appears to have dark gray left half and light gray right half; really a uniform color
Fourier transform: math algorithm that looks for "just the edges"
Blurry image: has no clear edges
Snakes illusion- apparent motion when going from the spiral pattern to a blank surface.
When surface is darker, your optic system integrates the images slower, so you'll see elss flicker on a darker screen
Vertical angle * horizontal angle = degrees-squared on the field of vision
Visual system focuses on detecting motion
Field-of-view vs. acuity compromise
Cones: High acuity [and color vision]
Rods: Low acuity and high sensitivity
If you hold a finger out at arm's length, the fingernail is about 1 degree wide.
There is a blind spot at a certain degree of the field that comes form the space where the optic nerve comes back out
Small blind spot aswell form the following: No rods directly ahead (0 degrees); only cones in that area
little depression at the center of your retina
Limiting acuity in the periphery is a part of the compromise; but need to move the eye around so that the strong-acuity area can cover different parts of the world
Ocular motor system: six muscles in three pairs (one does left-right, one pair does up-down, and one does rotation)
How much info is enough?
How quick is "just in time"?
saccades = rapid movement of eyes to look at a new object or region
Smooth Pursiut: stabilizes view of a moving object
Tremor, drift and microsaccades when you try to hold your eye steady
optokinetic response / optokinetic nystagmus
Have to serialize your visual-information intake
That presents problem of temporal-integration
Various devices to track eye movement in the laboratory
* Measuring reflection off the eye, in some way, is a common method
* Wearable eye tracker is the next development goal; starting to have success on that
Friday, March 21, 2008
(3/21/08)
Electrolysis: Put 2 metal rods into a beaker and run current through. You will see bubbling on each. One is all-hydrogen, one is all-oxygen. Would come up with soem ort of metod to trap the respective gases.
Need atleast 1.3 volts of current for electrolysis to work
Example solar panels he showed: 3 panels, each with a 2-row, 5-per-row arrangement
pn junction = diode = current can flow in 2 ways.
Electrons moving through a pn junction = sledding-hill analogy
Electrons slide down the hill (go between either end of the gap), releasing energy. Need energy to get pack up and redo the process; this energy is provided by photovoltaic energy striking the solar cell
Stack a whole bunch of fuel cells in series, then put some fuel-cell-banks in paralell, since each individual cell provides
----
Regular electricity:
Hook up batteries or solar cells in paralell - no voltage increase, but a current increase
Hook up batteries or cells in series: no current increase, but a voltage increase
power = voltage * current
Voltage - kind of like how high you put your water tower (how much pressure)
Current - kind of like water flowing through a pipe (how much flow)
Different electric applications require primarily one or the other
10^19 charges = coulomb
1 coulomb per second = 1 amp
----
Solar cells expensive; pay back over the course of relatively few years
PROVIDED, that local municipality supports "net metering", where your electricity meter runs backward when your solar array pumps power into the grid; this makes the payoff time quicker
Utilities don't want this cutting into their business
How does NanoPower relate to space colonization?
* Most of our stuff is low-orbit, so that's what we focus on; so even when we go out of low-Earth orbit, we use similar equipment.
* Air-generation systems would be very important to longterm space exploration; a problem we're more worried about than power generation
----
Radioisotope problem: A lot of energy, but we have to work on the terms of that radioisotope's half-life.
Spontaneously emits; no need to trigger it.
Only way to improve current is to have more mass
Need to produce many of these radioisotopes in a reactor
May still be useful at the lower current-rates of the second half-life
Decay in a regular pattern, so we can design accordingly.
---
Nanotubes: Some are metallic (normally conductive); some are semiconductors (unless you dope them, or shine light on them, often aren;t incredibly conductive.)
If we could make a batch of exactly identical nanotubes; we'd reach the Holy Grail of nanotech.
----
Steam reforming: pump steam through a fossil fuel; liberates the hydrogen, with CO2 as the byproduct.
However, the CO2 is trapped and used for industrial processes rather than pumped into the air
---
How are solar cells produced?
Different method:
polymer, silicon, 3 5 (3rd +5th column of periodic table, like gallium arsenide)
--
silicon-type: a bunch of boron atoms on surface of silicion; put that into a furnace; this speeds up the diffusion of the other half of the pn junction; so it "bakes in" the pn junction.
--
polymer-type: paint a negative polymer and a positive polymer on in alternating layers
NanoPower's advantage comes in making these other technologies more efficient and cheaper
--
Ethical debates with nanomaterials: toxicity concerns are the big one
--
Aren't nanotubes expensive b/c they're a new technology
Some types are, some types aren't (You can use laser vaporization, or you can burn stuff). It depends on what quality you need for the application in question.
--
Problem: waste with drained batteries that need to be disposed of. This is a real problem.
Lots of military equipment that goes through batteries like crazy, for instance.
Are flammable materials in batteries, but you could be aerosoling dangerous chemicals that were in the battery.
quantum dot = nano-scale piece of a semiconducting material. Rule sof macroscopic materials no longer really explain what going on; so we have to use quantum mechanics
Need atleast 1.3 volts of current for electrolysis to work
Example solar panels he showed: 3 panels, each with a 2-row, 5-per-row arrangement
pn junction = diode = current can flow in 2 ways.
Electrons moving through a pn junction = sledding-hill analogy
Electrons slide down the hill (go between either end of the gap), releasing energy. Need energy to get pack up and redo the process; this energy is provided by photovoltaic energy striking the solar cell
Stack a whole bunch of fuel cells in series, then put some fuel-cell-banks in paralell, since each individual cell provides
----
Regular electricity:
Hook up batteries or solar cells in paralell - no voltage increase, but a current increase
Hook up batteries or cells in series: no current increase, but a voltage increase
power = voltage * current
Voltage - kind of like how high you put your water tower (how much pressure)
Current - kind of like water flowing through a pipe (how much flow)
Different electric applications require primarily one or the other
10^19 charges = coulomb
1 coulomb per second = 1 amp
----
Solar cells expensive; pay back over the course of relatively few years
PROVIDED, that local municipality supports "net metering", where your electricity meter runs backward when your solar array pumps power into the grid; this makes the payoff time quicker
Utilities don't want this cutting into their business
Big Oil funding solar research; they want to get in on the "next big thing"
---How does NanoPower relate to space colonization?
* Most of our stuff is low-orbit, so that's what we focus on; so even when we go out of low-Earth orbit, we use similar equipment.
* Air-generation systems would be very important to longterm space exploration; a problem we're more worried about than power generation
----
Radioisotope problem: A lot of energy, but we have to work on the terms of that radioisotope's half-life.
Spontaneously emits; no need to trigger it.
Only way to improve current is to have more mass
Need to produce many of these radioisotopes in a reactor
May still be useful at the lower current-rates of the second half-life
Decay in a regular pattern, so we can design accordingly.
---
Nanotubes: Some are metallic (normally conductive); some are semiconductors (unless you dope them, or shine light on them, often aren;t incredibly conductive.)
If we could make a batch of exactly identical nanotubes; we'd reach the Holy Grail of nanotech.
----
Steam reforming: pump steam through a fossil fuel; liberates the hydrogen, with CO2 as the byproduct.
However, the CO2 is trapped and used for industrial processes rather than pumped into the air
---
How are solar cells produced?
Different method:
polymer, silicon, 3 5 (3rd +5th column of periodic table, like gallium arsenide)
--
silicon-type: a bunch of boron atoms on surface of silicion; put that into a furnace; this speeds up the diffusion of the other half of the pn junction; so it "bakes in" the pn junction.
--
polymer-type: paint a negative polymer and a positive polymer on in alternating layers
NanoPower's advantage comes in making these other technologies more efficient and cheaper
--
Ethical debates with nanomaterials: toxicity concerns are the big one
--
Aren't nanotubes expensive b/c they're a new technology
Some types are, some types aren't (You can use laser vaporization, or you can burn stuff). It depends on what quality you need for the application in question.
--
Problem: waste with drained batteries that need to be disposed of. This is a real problem.
Lots of military equipment that goes through batteries like crazy, for instance.
Are flammable materials in batteries, but you could be aerosoling dangerous chemicals that were in the battery.
quantum dot = nano-scale piece of a semiconducting material. Rule sof macroscopic materials no longer really explain what going on; so we have to use quantum mechanics
Wednesday, March 19, 2008
any way you burn carbon, you can make nanotubes.
Are made naturally with natural combustion of carbon, but we simply didn't know about them before
Nanotubes are almost to the scale of quantum mechanics
quantum confinement, how materials behave on those really small scales, is really important to nanotechnology
Laser vaporization: fire laser at graphite target with some metal.
Result is purified - boiling in acid (handles metal), burning (deals with soft carbon)
Electrical conductivity resistance of carbon nanotubes does not increase with temperature, whereas resistance of regular metals does
Are made naturally with natural combustion of carbon, but we simply didn't know about them before
Nanotubes are almost to the scale of quantum mechanics
quantum confinement, how materials behave on those really small scales, is really important to nanotechnology
Laser vaporization: fire laser at graphite target with some metal.
Result is purified - boiling in acid (handles metal), burning (deals with soft carbon)
Electrical conductivity resistance of carbon nanotubes does not increase with temperature, whereas resistance of regular metals does
(3/19/08) NanoPower lecture
Reminder:
Specific Power: power per each unit of mass
Radioisotope batteries: Long-term, but a small amount of current (have to wait for the half-life)
If you go for a short, quicker half-life, the battery doesn't last as long.
PMAD = Power Management and Distribution
Starshine: Looks like disco ball; used to monitor near-Earth-orbit drag
Solar activity is related to this drag; solar wind particles (sort of), but also
Nickel-metal-hydride batteries: Heavy (not the best specific power or energy density), but easily rechargeable
Lithium-ion: Better specific-power and energy density, but not as rechargeable
Lithium-ion batteries used in Earth-based electronics; so there's more R&D going on
Hydrogen fuel cells like batteries in design, but instead of passing ions back and forth, new ions (fuel) are pumped in.
Now how can nonomaterials help us with all of these power tasks?
Carbon nanotubes are used to improve performance
Inadvertent uses of nanotechnology exist farther back in history - Lycurgus cup comes to mind
buckminsterfullerenes discovered in 1980s: New ball-like form of carbon
Rolling up a sheet of paper = analogous to nanotubes. Can roll up the paper in different ways, and as such, can make different nanotubes. Some are metallic; some have varying degress of conductivity
Typically about a nanometer in diameter; can be hundreds or thousands of microns long; thus an unbelievably high aspect ratio.
Also a very-good thermal conductor
Strongest material known to man under tensile force
Solid-state physics law - Veidelman and Franz
* examined various conductors (gold, lead, etc)
* Ratio of thermal conductivity to electrical conductivity was the same for various materials
* SOme materials do violate this law, nanotubes aren't one of those.
Binding polymers used in actual battery applications, to keep the carbon-nanotube powder from getting all over the place.
Need at least 30% graphite to have conductivity
Need only one or two percent nano
Kind of like crossing a creek (creating a conductive path): Either pile rocks in, or lay one log across
Stronger, smoother plastic when nanotubes are used
Nanotube usage would speed-up the charge rate
Nanotubes group via van der waals effect.
Can make multi-wall nanotubes: easier to produce
Specific Power: power per each unit of mass
Radioisotope batteries: Long-term, but a small amount of current (have to wait for the half-life)
If you go for a short, quicker half-life, the battery doesn't last as long.
PMAD = Power Management and Distribution
Starshine: Looks like disco ball; used to monitor near-Earth-orbit drag
Solar activity is related to this drag; solar wind particles (sort of), but also
Nickel-metal-hydride batteries: Heavy (not the best specific power or energy density), but easily rechargeable
Lithium-ion: Better specific-power and energy density, but not as rechargeable
Lithium-ion batteries used in Earth-based electronics; so there's more R&D going on
Hydrogen fuel cells like batteries in design, but instead of passing ions back and forth, new ions (fuel) are pumped in.
Now how can nonomaterials help us with all of these power tasks?
Carbon nanotubes are used to improve performance
Inadvertent uses of nanotechnology exist farther back in history - Lycurgus cup comes to mind
buckminsterfullerenes discovered in 1980s: New ball-like form of carbon
Rolling up a sheet of paper = analogous to nanotubes. Can roll up the paper in different ways, and as such, can make different nanotubes. Some are metallic; some have varying degress of conductivity
Typically about a nanometer in diameter; can be hundreds or thousands of microns long; thus an unbelievably high aspect ratio.
Also a very-good thermal conductor
Strongest material known to man under tensile force
Solid-state physics law - Veidelman and Franz
* examined various conductors (gold, lead, etc)
* Ratio of thermal conductivity to electrical conductivity was the same for various materials
* SOme materials do violate this law, nanotubes aren't one of those.
Binding polymers used in actual battery applications, to keep the carbon-nanotube powder from getting all over the place.
Need at least 30% graphite to have conductivity
Need only one or two percent nano
Kind of like crossing a creek (creating a conductive path): Either pile rocks in, or lay one log across
Stronger, smoother plastic when nanotubes are used
Nanotube usage would speed-up the charge rate
Nanotubes group via van der waals effect.
Can make multi-wall nanotubes: easier to produce
Monday, March 17, 2008
(lecture 3/17/2008) - NanoPower introduction
Nanopower is power in space.
You can get this in two ways:
1 - Take fuel with you
2 - Scavenge (Scavenging includes solar power, and mining extraterrestrial environments)
When using solar, have batteries for when your craft isn't directly in the sun
Fuel cells were used on Apollo missions - they created electricity and water
Nuclear reactors can be used in space - a lot of power in a small weight; a lot of energy emitted in radioactive decay particles
Take forever to decay;so a long-life battery
Solar arrays - a lot of them are heavy,fragile silicon
90 % of current solar cells are silicon
SOlar cells only 30% efficient; you need heat dispersion
Chandra - X-ray observatory - X-ray astronomy can only be performed in space (too many X-rays get interfered with by Earth's atmosphere)
Mirror assembly had to be aligned with exacting precision.
Space SOlar Power
1) Convert solar photons into electricity
2) Efficiency
3) Mass Specific Power (power/mass)
4) Areal Specific Power (power/area)
Solar wind, v. small amount of drag, UV rays,micrometeoroids, space debris still a problem
Heavy glass currently necessary to shield solar cells
Anti-reflection coating
n-type semiconductor and p-type semiconductor - one has extra electrons, one has a deficiency of electrions.
pn junction - these two together; electrons bounce between them (that's the photovoltaic effect).
You need enough energy to kick the electron(s) between the levels.
SOme wavelengths have too much energy for this (that wastes heat).Some wavelengths have too little (not do enough). Some are just right [ Goldilocks Principle]
Concentrators concentrate the light,but they heat up the solar cell assembly. Generally aren't used
Space-power people very conservative
MOCVD
Metal organic chemical vapor deposition
OMVPE
How the semiconductors used in electronics are grown
If you drive electricity into a solar cell or other semiconductor thingies, you get light.
This is the basis for LASERs and LEDs.
If you connect batteries in series, the voltage adds, but the current is the same.
Small increases in efficicienty, even fractions of a percent, are a huge deal.
When semiconductor reduced to the nano-scale, its band gap changes based on the size.
Gets into quantum mechanics
You can get this in two ways:
1 - Take fuel with you
2 - Scavenge (Scavenging includes solar power, and mining extraterrestrial environments)
When using solar, have batteries for when your craft isn't directly in the sun
Fuel cells were used on Apollo missions - they created electricity and water
Nuclear reactors can be used in space - a lot of power in a small weight; a lot of energy emitted in radioactive decay particles
Take forever to decay;so a long-life battery
Solar arrays - a lot of them are heavy,fragile silicon
90 % of current solar cells are silicon
SOlar cells only 30% efficient; you need heat dispersion
Chandra - X-ray observatory - X-ray astronomy can only be performed in space (too many X-rays get interfered with by Earth's atmosphere)
Mirror assembly had to be aligned with exacting precision.
Space SOlar Power
1) Convert solar photons into electricity
2) Efficiency
3) Mass Specific Power (power/mass)
4) Areal Specific Power (power/area)
Solar wind, v. small amount of drag, UV rays,micrometeoroids, space debris still a problem
Heavy glass currently necessary to shield solar cells
Anti-reflection coating
n-type semiconductor and p-type semiconductor - one has extra electrons, one has a deficiency of electrions.
pn junction - these two together; electrons bounce between them (that's the photovoltaic effect).
You need enough energy to kick the electron(s) between the levels.
SOme wavelengths have too much energy for this (that wastes heat).Some wavelengths have too little (not do enough). Some are just right [ Goldilocks Principle]
Concentrators concentrate the light,but they heat up the solar cell assembly. Generally aren't used
Space-power people very conservative
MOCVD
Metal organic chemical vapor deposition
OMVPE
How the semiconductors used in electronics are grown
If you drive electricity into a solar cell or other semiconductor thingies, you get light.
This is the basis for LASERs and LEDs.
If you connect batteries in series, the voltage adds, but the current is the same.
Small increases in efficicienty, even fractions of a percent, are a huge deal.
When semiconductor reduced to the nano-scale, its band gap changes based on the size.
Gets into quantum mechanics
Friday, March 14, 2008
Questions
1 - Inadverntent Vaccination
Vaccines that are modified viruses - problem of *those* being transmitted
* Depends on characteristics of the specific modified virus
* Some people will be more-vulnerable to even a weakened modified virus
* Can address this by heavily customizing the modified virus
2 - VSV and interferon
Why isn't interferon beign released form VSV-infected cells?
Does this have anything to do with interferon.
Either VSV isn't inducing interferon, or it;s stopping interferon that is getting released.
3 - What if the vaccination causes a disease?
* The question addressed by Phase I clinical trials (giving vaccine to previously-healthy people)
* The question of pharmacology: the risk/reward analysis
4 - Sanitation
* If over-sanitation is increasing susceptibilty to some diseases, should we consciously tone it down?
Yes.
Well, not in a hospital environment
* Natural flora - body has loads of "good" bacteria and viruses in it at any one time.
Don't want to kill those.
Vaccines that are modified viruses - problem of *those* being transmitted
* Depends on characteristics of the specific modified virus
* Some people will be more-vulnerable to even a weakened modified virus
* Can address this by heavily customizing the modified virus
2 - VSV and interferon
Why isn't interferon beign released form VSV-infected cells?
Does this have anything to do with interferon.
Either VSV isn't inducing interferon, or it;s stopping interferon that is getting released.
3 - What if the vaccination causes a disease?
* The question addressed by Phase I clinical trials (giving vaccine to previously-healthy people)
* The question of pharmacology: the risk/reward analysis
4 - Sanitation
* If over-sanitation is increasing susceptibilty to some diseases, should we consciously tone it down?
Yes.
Well, not in a hospital environment
* Natural flora - body has loads of "good" bacteria and viruses in it at any one time.
Don't want to kill those.
Gene Therapy and Viral Vectors
Gene Therapy: putting genes into the body's relevant cells to replace a screwed-up gene and thus fix a genetic disease.
Viruses can be used as delivery vectors for this.
(not the only vector: gene guns, injections, etc.)
Idea: apply gene therapy to fetuses (fewer cells to treat)
-------
Viruses and cancer
Oncolytic Viruses
"onco"- cancer
"lytic" - killing
Virotherapy: a therapy that seeks to harness the natural properties of viruses to aid in the fight against cancer
Strategies:
Viruses modified so as to only bind to cancer cells. (Finding the 'markers' is difficult)
Viruses "armed" with different/more genes to enhance effect
Viruses modified so that they can only reproduce in abnormal cells
Great idea in theory; how will it work out in process.
Also, tumor cells tend to lack proper interferon response.
--------
Advantages of VSV in particular come into play
--------
Political problems a danger to worldwide disease-eradication campaigns
Vaccination campaigns always harder in developing countries anyways.
W/ polio, virus changes a bit
Viruses can be used as delivery vectors for this.
(not the only vector: gene guns, injections, etc.)
Idea: apply gene therapy to fetuses (fewer cells to treat)
-------
Viruses and cancer
Oncolytic Viruses
"onco"- cancer
"lytic" - killing
Virotherapy: a therapy that seeks to harness the natural properties of viruses to aid in the fight against cancer
Strategies:
Viruses modified so as to only bind to cancer cells. (Finding the 'markers' is difficult)
Viruses "armed" with different/more genes to enhance effect
Viruses modified so that they can only reproduce in abnormal cells
Great idea in theory; how will it work out in process.
Also, tumor cells tend to lack proper interferon response.
--------
Advantages of VSV in particular come into play
--------
Political problems a danger to worldwide disease-eradication campaigns
Vaccination campaigns always harder in developing countries anyways.
W/ polio, virus changes a bit
Wednesday, March 12, 2008
(3/12/08 lecture): Viruses as friends
Knowledge of cellular mechanisms
Foundation of molecular biology
Technical development
Knowledge of disease
-Vaccines-
* Some made from weakened versions of the target virus
* Some made form another virus
Vaccine trials = need a lot of $
Foundation of molecular biology
Technical development
Knowledge of disease
-Vaccines-
* Some made from weakened versions of the target virus
* Some made form another virus
Vaccine trials = need a lot of $
(3/12/08 lecture): More about viruses
Vuris mess with the DNA-RNA-protein model that is a major tenet of biology
----
Different viruses progress differently after they infect you - graphs on the way
Consequences of viral infections:
* Some are fatal
* Some related to congenital diseases
* Contributory factor to cancer (like HPV --> cervical cancer)
* COntribute to other diseases
* Economic impact
---------
*Some viruses asymptomatic - not all viruses make you sick
----------
Pathogenesis: *how* viruses cause disease
Eyes, mouth, skin [abrasion, injection], respiratory tract, alimentary canal, urogenital tract, anus
^ Different viruses target different areas
Attachment: Some viruses work with a cell receptor unique to a specific type of cell.
Once attached, virus gets thorugh the cell membrane and inside the cell
The few genes/proteins in a virus genome aren't enough to do what it needs to do, so it gets that by hijacking the host cell.
----
Vesicular Stomatitis Virus
Preferred host: cattle
Can target other organisms if the virus is in a larger concentration
Can kill a cow in about a week
Only has 5 proteins
RNA degrades pretty quickly in the open environment, N-protein of VSV guards it.
Can easily add a 'tracking' gene (i.e. staining/coloration)
--------
Virus invasion of a cell triggers the cell to produce "interferon" (cellular distress call)
Some viruses interfere with interferon
----
Different viruses progress differently after they infect you - graphs on the way
Consequences of viral infections:
* Some are fatal
* Some related to congenital diseases
* Contributory factor to cancer (like HPV --> cervical cancer)
* COntribute to other diseases
* Economic impact
---------
*Some viruses asymptomatic - not all viruses make you sick
----------
Pathogenesis: *how* viruses cause disease
Eyes, mouth, skin [abrasion, injection], respiratory tract, alimentary canal, urogenital tract, anus
^ Different viruses target different areas
Attachment: Some viruses work with a cell receptor unique to a specific type of cell.
Once attached, virus gets thorugh the cell membrane and inside the cell
The few genes/proteins in a virus genome aren't enough to do what it needs to do, so it gets that by hijacking the host cell.
----
Vesicular Stomatitis Virus
Preferred host: cattle
Can target other organisms if the virus is in a larger concentration
Can kill a cow in about a week
Only has 5 proteins
RNA degrades pretty quickly in the open environment, N-protein of VSV guards it.
Can easily add a 'tracking' gene (i.e. staining/coloration)
--------
Virus invasion of a cell triggers the cell to produce "interferon" (cellular distress call)
Some viruses interfere with interferon
What prevented pilio's eradication in 2000?
What prevented polio's eradication in 2000?
First, it is important to note that a lot of progress *was* mad ein polio reduction, confining it to just some areas of the Third World by 2000.
This means:
A.) Society was on the right track
B.) Logistical problems having to do with the Third World might have stood in the way
It's not like anti-polio workers "packed up and went home" after the 2000 deadline, so a pattern of progress continues.
Global goal to eradicate polio was set in 1988, 11 years *after* the declared eradication of smallpox. So,logically, a project of this scope would take a while.
"by the end of 2006, only four countries remained which had never interrupted endemic transmission of wild poliovirus (Nigeria, India, Pakistan and Afghanistan)"
This goes back to the Third-World logistical issues above, and Afghanistan has been ravaged by war and civil strife for decades.
First, it is important to note that a lot of progress *was* mad ein polio reduction, confining it to just some areas of the Third World by 2000.
This means:
A.) Society was on the right track
B.) Logistical problems having to do with the Third World might have stood in the way
It's not like anti-polio workers "packed up and went home" after the 2000 deadline, so a pattern of progress continues.
Global goal to eradicate polio was set in 1988, 11 years *after* the declared eradication of smallpox. So,logically, a project of this scope would take a while.
"by the end of 2006, only four countries remained which had never interrupted endemic transmission of wild poliovirus (Nigeria, India, Pakistan and Afghanistan)"
This goes back to the Third-World logistical issues above, and Afghanistan has been ravaged by war and civil strife for decades.
Monday, March 10, 2008
Viruses: Friend or Foe (3/10/2008 lecture)
Today - focus on traditional bad viruses
Wednesday - more-positive uses of viruses
Long bad history
Egypt - withered legs (from polio?), smallpox lesions
Homer (the old Greek one, not the Simpsons one) discussed rabid dogs
Viruses have reshaped human history
Smallpox - major tactical advantage Europeans had vs. Native Americans
Influenza - post-WWI not the only major epidemic
Polio
HIV
-Role of biological warfare-
Smallpox - very contagious - psutiles of smallpox victims burst to spread lots more of the virus
Smallpox - only infects humans
Declared eradication in 1977
Influenza - smaller particles than smallpox virus
Influenza epidemics - a lot of them, but post-WWI was the worst - 20,000,000 dead (double WWI combat deaths)
1920 epidemic hit mostly the very young and very old, but also deaths inbetween,hich was shocking
Polio - FDR's suffering form the disease galvanized response
Polio often causes paralysis. Iron lung necessary if diaphragm suffers from the paralysis
Polio epidemic in 1952 - side-effect of cleaner society (less mild immunities built up)
HIV-AIDs - Misunderstood in the beginning, misunderstanding-based public fears
Africa being hit especially hard
Polio elimination followed smallpox. Polio endemic area reduced to India and parts of Africa
Chicken v. Egg - viruses or bacteria?
Were virus-like things the first replicators? Modern virii need cells to replicate, did the ancient
ones?
Okay, some bad things that viruses have done.
Now what are they?
They are very very small (20-400 nanometers)
DNA or RNA in genome
Protein shell
Some, such as HIV, have a lipid (fat) envelope
*obligate intracellular parasites*
Different viruses can affect all different types of organisms (any of the other phyla)
Filterable if you can do a filter small enough
Wednesday - more-positive uses of viruses
Long bad history
Egypt - withered legs (from polio?), smallpox lesions
Homer (the old Greek one, not the Simpsons one) discussed rabid dogs
Viruses have reshaped human history
Smallpox - major tactical advantage Europeans had vs. Native Americans
Influenza - post-WWI not the only major epidemic
Polio
HIV
-Role of biological warfare-
Smallpox - very contagious - psutiles of smallpox victims burst to spread lots more of the virus
Smallpox - only infects humans
Declared eradication in 1977
Influenza - smaller particles than smallpox virus
Influenza epidemics - a lot of them, but post-WWI was the worst - 20,000,000 dead (double WWI combat deaths)
1920 epidemic hit mostly the very young and very old, but also deaths inbetween,hich was shocking
Polio - FDR's suffering form the disease galvanized response
Polio often causes paralysis. Iron lung necessary if diaphragm suffers from the paralysis
Polio epidemic in 1952 - side-effect of cleaner society (less mild immunities built up)
HIV-AIDs - Misunderstood in the beginning, misunderstanding-based public fears
Africa being hit especially hard
Polio elimination followed smallpox. Polio endemic area reduced to India and parts of Africa
Chicken v. Egg - viruses or bacteria?
Were virus-like things the first replicators? Modern virii need cells to replicate, did the ancient
ones?
Okay, some bad things that viruses have done.
Now what are they?
They are very very small (20-400 nanometers)
DNA or RNA in genome
Protein shell
Some, such as HIV, have a lipid (fat) envelope
*obligate intracellular parasites*
Different viruses can affect all different types of organisms (any of the other phyla)
Filterable if you can do a filter small enough
What is this?
This is a blog I'm using as the repository for notes and other related class materials for one of my RIT classes, called 'Frontiers of Science'
I have a laptop out during class; generally typing my notes directly into Blogger's 'new post' form. [Thank you for automatically saving my drafts. :)]
I have a laptop out during class; generally typing my notes directly into Blogger's 'new post' form. [Thank you for automatically saving my drafts. :)]
Subscribe to:
Posts (Atom)