Please stop by an gives us your comments about the content of this blog in terms of its use for a better understanding of Uni 1 - The Universe.
What do you think we can include to improve it and why? What kind of information do you think could be provided to help students understand this unit better?
Sunday, June 1, 2008
Thursday, May 29, 2008
Cosmology Glossary
Big Bang:
The Big Bang is a cosmological model of the universe that has become well supported by several independent observations. After Edwin Hubble discovered that galactic distances were generally proportional to their redshifts in 1929, this observation was taken to indicate that the universe is expanding. If the universe is seen to be expanding today, then it must have been smaller, denser, and hotter in the past. This idea has been considered in detail all the way back to extreme densities and temperatures, and the resulting conclusions have been found to conform very closely to what is observed.
Big Crunch:
Is one possible scenario for the ultimate fate of the universe, in which the metric expansion of space eventually reverses and the universe recollapses, ultimately ending as a black hole singularity. If there is enough matter in the Universe eventually gravitaional forces will stop its expansion. When this happens gravity will cause the universe to reverse its direction and begin to collapse under its own weight. This phase of the Universe's life is known as the Big Crunch.
Black Holes:
They are places where ordinary gravity has become so extreme that it overwhelms all other forces in the Universe. Once inside, nothing can escape a black hole's gravity — not even light.
Blueshift:
Refers to a shortening of a transmitted signal's wavelength, and/or an increase in its frequency. The name comes from the fact that the shorter-wavelength end of the optical spectrum is the blue (or violet) end, hence, when visible light is compacted in wavelength, it is "shifted towards the blue", or "blue-shifted". Some possible causes of blue shift in astronomy are: 1. Movement of the source towards us, as seen in: a) the edge of a rotating galaxy moving towards us; b) In blazars which propel relativistic jets towards us. 2. Gravitational effects.
Cosmic Microwave Background Radiation:
In cosmology, the cosmic microwave background radiation is a form of electromagnetic radiation discovered in 1965 that fills the entire universe. It has a thermal black body spectrum at a temperature of 2.725 kelvin. Thus the spectrum peaks in the microwave range at a frequency of 160.2 GHz, corresponding to a wavelength of 1.9 mm. Most cosmologists consider this radiation to be the best evidence for the Big Bang model of the universe.
Cosmological Constant:
In physical cosmology, the cosmological constant (usually denoted by the Greek capital letter lambda: Λ) was proposed by Albert Einstein as a modification of his original theory of general relativity to achieve a stationary universe. Einstein abandoned the concept after the observation of the Hubble redshift indicated that the universe might not be stationary. However, the discovery of cosmic acceleration in the 1990s has renewed interest in a cosmological constant.
Cosmological Principle:
Is a principle invoked in cosmology that, when applied, severely restricts the large variety of possible cosmological theories. It follows from the observation of the Universe on a large scale, and states that:
On large spatial scales, the Universe is homogeneous and isotropic.
Or simply put, the universe is the same everywhere on a large scale.
This principle means that averaged over large enough distances, one part of the Universe looks approximately like any other part.
Lookback Time:
Is a phenomenon that, owing to the finite velocity of light, the more distant an object being observed, the older is the information received from it. A galaxy one billion light-years away, for instance, is seen as it looked one billion years ago. Light travels at the finite speed of 300,000 kilometers per second. The Sun is so distant that light takes 8.3 minutes to travel from it to Earth. Hence, the Sun has a lookback time of 8.3 minutes; we see it as it was 8.3 minutes ago. The Andromeda Galaxy has a lookback time of 2 million years; we see it as it was 2 million years ago
Neutron Star:
A neutron star is formed from the collapsed remnant of a massive star; i.e. a Type II, Type Ib or Type Ic supernova. Models predict that neutron stars consist mostly of neutrons, hence the name. Such stars are very hot, as supported by the Pauli exclusion principle indicating repulsion between neutrons. A neutron star is one of the few possible conclusions of stellar evolution.
Quasars:
Are the brightest and most distant objects in the known universe. In the early 1960's, quasars were referred to as radio stars because they were discovered to be a strong source of radio waves. The quasars themselves can burn up to the energy of a trillion suns and recent evidence shows that this may all happen because of black holes. What we know about quasars is that they have great energy, but are not immense in size
Redshift:
In physics and astronomy, redshift occurs when the electromagnetic radiation, usually visible light, that is emitted from or reflected off an object is shifted towards the (less energetic) red end of the electromagnetic spectrum. More generally, redshift is defined as an increase in the wavelength of electromagnetic radiation received by a detector compared with the wavelength emitted by the source. An object that is receding from us at very high velocities has its spectral lines red-shifted.
Relativity:
General relativity is a theory of gravitation developed by Einstein in the years 1907–1915 that generalizes Isaac Newton´s original theory of gravity. The development of general relativity began with the equivalence principle, under which the states of accelerated motion and being at rest in a gravitational field (for example when standing on the surface of the Earth) are physically identical. In this theory gravity is supposed to be a distortion of space and time itself.
http://en.wikipedia.org/
http://hubblesite.org/explore_astronomy/black_holes/home.html ,
http://www.seasky.org/cosmic/sky7a09.html ,
http://www.site.uottawa.ca:4321/astronomy/index.html#lookbacktime ,
http://www.rdrop.com/users/green/school/quasars.htm , http://wise.ssl.berkeley.edu/glossary/lookback_time.html
The Big Bang is a cosmological model of the universe that has become well supported by several independent observations. After Edwin Hubble discovered that galactic distances were generally proportional to their redshifts in 1929, this observation was taken to indicate that the universe is expanding. If the universe is seen to be expanding today, then it must have been smaller, denser, and hotter in the past. This idea has been considered in detail all the way back to extreme densities and temperatures, and the resulting conclusions have been found to conform very closely to what is observed.
Big Crunch:
Is one possible scenario for the ultimate fate of the universe, in which the metric expansion of space eventually reverses and the universe recollapses, ultimately ending as a black hole singularity. If there is enough matter in the Universe eventually gravitaional forces will stop its expansion. When this happens gravity will cause the universe to reverse its direction and begin to collapse under its own weight. This phase of the Universe's life is known as the Big Crunch.
Black Holes:
They are places where ordinary gravity has become so extreme that it overwhelms all other forces in the Universe. Once inside, nothing can escape a black hole's gravity — not even light.
Blueshift:
Refers to a shortening of a transmitted signal's wavelength, and/or an increase in its frequency. The name comes from the fact that the shorter-wavelength end of the optical spectrum is the blue (or violet) end, hence, when visible light is compacted in wavelength, it is "shifted towards the blue", or "blue-shifted". Some possible causes of blue shift in astronomy are: 1. Movement of the source towards us, as seen in: a) the edge of a rotating galaxy moving towards us; b) In blazars which propel relativistic jets towards us. 2. Gravitational effects.
Cosmic Microwave Background Radiation:
In cosmology, the cosmic microwave background radiation is a form of electromagnetic radiation discovered in 1965 that fills the entire universe. It has a thermal black body spectrum at a temperature of 2.725 kelvin. Thus the spectrum peaks in the microwave range at a frequency of 160.2 GHz, corresponding to a wavelength of 1.9 mm. Most cosmologists consider this radiation to be the best evidence for the Big Bang model of the universe.
Cosmological Constant:
In physical cosmology, the cosmological constant (usually denoted by the Greek capital letter lambda: Λ) was proposed by Albert Einstein as a modification of his original theory of general relativity to achieve a stationary universe. Einstein abandoned the concept after the observation of the Hubble redshift indicated that the universe might not be stationary. However, the discovery of cosmic acceleration in the 1990s has renewed interest in a cosmological constant.
Cosmological Principle:
Is a principle invoked in cosmology that, when applied, severely restricts the large variety of possible cosmological theories. It follows from the observation of the Universe on a large scale, and states that:
On large spatial scales, the Universe is homogeneous and isotropic.
Or simply put, the universe is the same everywhere on a large scale.
This principle means that averaged over large enough distances, one part of the Universe looks approximately like any other part.
Lookback Time:
Is a phenomenon that, owing to the finite velocity of light, the more distant an object being observed, the older is the information received from it. A galaxy one billion light-years away, for instance, is seen as it looked one billion years ago. Light travels at the finite speed of 300,000 kilometers per second. The Sun is so distant that light takes 8.3 minutes to travel from it to Earth. Hence, the Sun has a lookback time of 8.3 minutes; we see it as it was 8.3 minutes ago. The Andromeda Galaxy has a lookback time of 2 million years; we see it as it was 2 million years ago
Neutron Star:
A neutron star is formed from the collapsed remnant of a massive star; i.e. a Type II, Type Ib or Type Ic supernova. Models predict that neutron stars consist mostly of neutrons, hence the name. Such stars are very hot, as supported by the Pauli exclusion principle indicating repulsion between neutrons. A neutron star is one of the few possible conclusions of stellar evolution.
Quasars:
Are the brightest and most distant objects in the known universe. In the early 1960's, quasars were referred to as radio stars because they were discovered to be a strong source of radio waves. The quasars themselves can burn up to the energy of a trillion suns and recent evidence shows that this may all happen because of black holes. What we know about quasars is that they have great energy, but are not immense in size
Redshift:
In physics and astronomy, redshift occurs when the electromagnetic radiation, usually visible light, that is emitted from or reflected off an object is shifted towards the (less energetic) red end of the electromagnetic spectrum. More generally, redshift is defined as an increase in the wavelength of electromagnetic radiation received by a detector compared with the wavelength emitted by the source. An object that is receding from us at very high velocities has its spectral lines red-shifted.
Relativity:
General relativity is a theory of gravitation developed by Einstein in the years 1907–1915 that generalizes Isaac Newton´s original theory of gravity. The development of general relativity began with the equivalence principle, under which the states of accelerated motion and being at rest in a gravitational field (for example when standing on the surface of the Earth) are physically identical. In this theory gravity is supposed to be a distortion of space and time itself.
http://en.wikipedia.org/
http://hubblesite.org/explore_astronomy/black_holes/home.html ,
http://www.seasky.org/cosmic/sky7a09.html ,
http://www.site.uottawa.ca:4321/astronomy/index.html#lookbacktime ,
http://www.rdrop.com/users/green/school/quasars.htm , http://wise.ssl.berkeley.edu/glossary/lookback_time.html
New Vocabulary
1. Attest: (verb) Authenticate, affirm to be true, genuine, or correct, as in an official capacity. "I attest this signature"// Establish or verify the usage of; "This word is not attested until 1993" // Provide evidence for; stand as proof of; show by one's behavior, attitude, or external attributes; "His high fever attested to his illness"; "The buildings in Rome manifest a high level of architectural sophistication".
2. Average: (noun) a statistic describing the location of a distribution; "it set the norm for American homes"
3. Axis: (noun) The center around which something rotates. // The 2nd cervical vertebra; serves as a pivot for turning the head.
4. Crane: (noun) Large long-necked wading bird of marshes and plains in many parts of the world // Lifts and moves heavy objects; lifting tackle is suspended from a pivoted boom that rotates around a vertical axis // (verb) Stretch (the neck) so as to see better; "The women craned their necks to see the President drive by"
5. Disclaimer: (noun) a written statement denying legal responsibility.//Denial of any connection with or knowledge of.
6. Doomed: (noun) People who are destined to die soon; "the agony of the doomed was in his voice" // (adj.) Marked for certain death; "the black spot told the old sailor he was doomed" // (usually followed by `to') Determined by tragic fate; "doomed to unhappiness" // Marked by or promising bad fortune; "their business venture was doomed from the start"; "an ill-fated business venture"; "an ill-starred romance".
7. Ebb: (noun) The outward flow of the tide // A gradual decline (in size or strength or power or number) // (verb) fall away or decline; "The patient's strength ebbed away" // Hem in fish with stakes and nets so as to prevent them from going back into the sea with the ebb.
8. Fate: (noun) an event (or a course of events) that will inevitably happen in the future. //Destine; the ultimate agency that predetermines the course of events (often personified as a woman); "we are helpless in the face of Destiny”
9. Fiery: (adj.) like or suggestive of fire; "the burning sand"; "a fiery desert wind"; "an igneous desert atmosphere"
10. Flare up: (verb) Erupt or intensify suddenly; "Unrest erupted in the country"; "Tempers flared at the meeting"; "The crowd irrupted into a burst of patriotism" // Ignite quickly and suddenly, especially after having died down; "the fire flared up and died down once again"
11. Flee: (verb) run away quickly; leave; go forth; go away "He threw down his gun and fled"
12. Overlooking: (adj.) Used of a height or viewpoint; "a commanding view of the ocean"; "looked up at the castle dominating the countryside"; "the balcony overlooking the ballroom".
13. Plotted: (adj.) Planned in advance; "with malice aforethought”
14. Prolific: (adj.) Bearing in abundance especially offspring; "flying foxes are extremely prolific"; "a prolific pear tree".
15. Suck: (verb) draw into the mouth by creating a practical vacuum in the mouth; "suck the poison from the place where the snake bit"; "suck on a straw"; "the baby sucked on the mother's breast"
American Pocket-Chambers English Dictionary, 2nd Edition, Larousse.
English Dictionary (2008)[http://www.wordreference.com/es] [Consulted on 26/05/08]
The Men Behind
Nicolaus Copernicus
(February 19, 1473 – May 24, 1543) was the first astronomer to formulate a scientifically based heliocentric cosmology that displaced the Earth from the center of the universe. His epochal book, De revolutionibus orbium coelestium (On the Revolutions of the Celestial Spheres), is often regarded as the starting point of modern astronomy and the defining epiphany that began the Scientific Revolution. Copernicus was a mathematician, astronomer, physician, classical scholar, translator, Catholic cleric, jurist, governor, military leader, diplomat and economist.
Galileo Galilei
(15 February 1564, Pisa, Italy– 8 January 1642, Arcetri, Tuscany Italy ). He was a physicist, mathematician, astronomer, and a philosopher who made several discoveries, which were relevant for the Scientific Revolution. His achievements include improvements to the telescope and consequent astronomical observations, and support for Copernicanism. The motion of uniformly accelerated objects, taught in nearly all high school and introductory college physics courses, was studied by Galileo as the subject of kinematics. His contributions to observational astronomy include the discovery of the four largest satellites of Jupiter, named the Galilean moons in his honour, and the observation and analysis of sunspots. Galilei observed the Milky Way and found it to be a pack of stars, so densely that they appeared to be clouds from the Earth. Galileo also worked in applied science and technology, improving compass design.
Isaac Newton 
(4 January 1643 – 31 March 1727 ) was an English physicist, mathematician, astronomer, natural philosopher, alchemist and theologian. His Philosophiæ Naturalis Principia Mathematica, published in 1687, is said to be the greatest single work in the history of science. In this work, Newton described universal gravitation and the three laws of motion, laying the groundwork for classical mechanics, which dominated the scientific view of the physical universe for the next three centuries and is the basis for modern engineering. Newton showed that the motions of objects on Earth and of celestial bodies are governed by the same set of natural laws by demonstrating the consistency between Kepler's laws of planetary motion and his theory of gravitation, thus removing the last doubts about heliocentrism and advancing the scientific revolution.
Albert Einstein
(March 14, 1879 at Ulm, in Württemberg, Germany– April 18, 1955)Einstein postulated that the correct interpretation of the special theory of relativity must also furnish a theory of gravitation and in 1916 he published his paper on the general theory of relativity. During this time he also contributed to the problems of the theory of radiation and statistical mechanics. Einstein's most important works include Special Theory of Relativity (1905), Relativity (English translations, 1920 and 1950), General Theory of Relativity (1916), Investigations on Theory of Brownian Movement (1926), and The Evolution of Physics (1938).
Copernicus, Galiei, Newton, Einstein. Retrieved from: http://en.wikipedia.org/wiki/
Christian Andreas Doppler
(1803 – 1853) Christian Doppler studied mathematics and astronomy in Czechoslovakia and Austria. He explained that the perceived change of frequency in light and sound waves was due to the relative motion of the source and the observer. His ideas helped pave the way for the idea that the universe is expanding, and made it possible to follow weather patterns by tracking electromagnetic radio waves. During his days as professor in Praga he published more than 50 articles in the areas of mathematics, phisics and astronomy.
The Doppler Shift was discovered by Christian Doppler when he noticed that sound travels in waves much like waves on the surface of the ocean. Doppler also noticed that when the source of the sound is moving, the pitch of the sound is different, depending on whether the source is moving toward or away from the observer.
Doppler Shift also works with light. When a light source is moving toward you, the light becomes more blue (called a blue shift). When a light source is moving away from you, the light becomes redder (called a red shift). And the faster something is moving, the farther the light is shifted. But the Doppler shift for light is very subtle and cannot be detected with the naked eye. Scientists use a device called a spectroscope to measure Doppler Shift and determine how fast stars and galaxies are moving.
http://www.astro.ucla.edu/~wright/doppler.htm
http://es.wikipedia.org/wiki/Christian_Andreas_Doppler
Edwin Hubble
(1889 – 1953) He was an American Astronomer. Hubble did some of the most important discoveries of the astronomy. Among them, we could find:
He determined the existence of several other galaxies, such as our Milky Way, by taking many photographs of Cepheid variables through 100 inch reflecting Hooker telescope, proving they were outside our galaxy
Hubble had also devised a classification system for the various galaxies he observed, sorting them by content, distance, shape, and brightness
He also discovered that the degree of redshift observed in light coming from a galaxy increased in proportion to the distance of that galaxy from the Milky Way. This became known as Hubble’s Law, and would help establish that the universe is expanding.
If universe is expanding outwards, it must have been coming from a central point, and that something must have caused that expansion to begin with. Thus, Hubble’s discoveries lead to the formulation of the Big Bang theory.
http://antwrp.gsfc.nasa.gov/diamond_jubilee/1996/sandage_hubble.html
George Gamow
(1904 – 1968) He was a Russian-American nuclear physicist and author. Some of his various scientific contributions were:
In 1928 he formulated a theory of radioactive decay and worked on the application of nuclear physics to problems of stellar evolution.
He was one of the first proponents of the “Big Bang” theory, and also one of its more valuable defenders
He was one of the first scientists who thought that the present levels of hydrogen and helium could be explained by the reactions ocurred during the Big Bang.
Gamow predicted that the afterglow of “Big Bang” radiation would have cooled down after billions of years, filling the universe with a radiation five degrees above the absolute zero (0 ºK = -273 ºC)
He developed equations for the mass and radius of a primordial galaxy (wich contains about one hundred billion stars)
http://personal.ifae.es/redondo/physics/biog/Gamow.pdf
Stephen Hawking
(1942… Present) He is a British theoretical physicist. He is also the Lucasian Professor of Mathematics at the University of Cambridge. He is known for his contributions to the fields of theoretical cosmology and quantum gravity.
Hawking combined the fields of Quantum Theory and General Relativity through his research. This combination of the two fields happened after he was able to show that when the General Theory of Relativity is utilized, this implies that both time and space would have a defined starting and ending point. The beginning would occur during the big bang and the end would be inside of the black holes.
Hawking theorized that black holes were not entirely black but in fact emitted certain types of radiation. Over time, the black holes could evaporate and ultimately disappear from existence.
Hawking also contributed to the idea of imaginary time. This sort of time is somewhat related to the idea of imaginary numbers (multiples of the square root of -1). In this realm of thought and existence, he has theorized that the universe would have no boundaries.
Hawking has also had an interest in the classification of gravitational waves.
Hawking has theorized that the arrow of time can only point in one direction which is forward.
Two more postulates that Hawking has formulated include wormholes and baby universes. He theorizes that only subatomic particles can travel through wormholes to alternate universes, if they in fact exist. Baby universes are another modification of the Big Bang Theory in that after the explosion many different universes were created like bubbles. Also, each bubble has the ability to create another baby universe.
Both Hawking and Kip Thorne have theorized that a singularity exists in the interior of a black hole.
In 2004 Hawking discovered that he was wrong about his hypotheses in wich he thought that a black hole destroys everything that falls into it. He did solve the enigma of the information in black holes: he claimed that he could now prove that this information wasn’t lost.
http://www.bbc.co.uk/sn/tvradio/programmes/horizon/hawking_prog_summary.shtml
http://www.usd.edu/phys/courses/phys300/gallery/clark/hawking.html
About Reading Skills
Title:
Is a name given to a text with the intention of identifying the subject of the reading. In occasions, the title of text hooks to the lector. It briefly describes the general vision of the text.
Topic:
In order to have a better understanding of the text it is really important to have a previous knowledge of what it is going to be read. The topic of a text is a phrase or a group of words that head a text and announce or summarize its content, it answers the following question:
“What is the text/passage about?”
Main Idea:
Is a sentence or a phrase that explains the central thought or message that the author wants to transmit. It helps readers to remember important information. All the information in the text supports the main idea. It answers the following question:
“What are the most important issues about the topic
being discussed in the passage/text?”
Usually before reading a text, there are questions that “the reader” should ask herself/himself which introduce him/her to the reading and helps to understand better the information. These questions are:- The title of the following text is______.
- What do you already know about the topic? Mention some facts.
- Write down six key words you expect to find in the text.
- Write down as many associations as you can think of for each one.
- Look at the first and last paragraphs of the text. Write a sentence you think it will describe the general idea of the text.
- Write down several things you would like to find out in the text.
http://www.upv.es/jugaryaprender/ingles/reading.htm
http://www.beaconlearningcenter.com/weblessons/GetTheIdea/default.htm
http://www.thefreedictionary.com/title
http://vclass.mtsac.edu:920/readroom/Mainidea.htm
Purpose of Paragraphs:
Is used to present a definition or explanation of a term, or to present arguments or a point of view about something. Also, the purpose of paragrahs is to interrelate sentences that develop a central topic. Paragraphs are generally governed by a topic sentence, and it has its own unity and coherence and is an integral part of the logical development of an essay.
Supporting Ideas:
Are sentences that explain, or give details about the main idea. Supporting ideas tell how, what, where, why, how much or how many details about main idea and the relationship between details and main ideas, increasing your comprehension of the topic in question.
http://www.google.co.ve/url?sa=X&start=1&oi=define&q,
http://www.google.co.ve/url?sa=X&start=1&oi=define&q,
http://www.pearsoned.ca/text/flachmann4/gloss_iframe.html&usg=AFQjCNFLwPwNcjO3KSDcCwN70yGiOIkjeg, http://www.nottingham.ac.uk/academicsupport/materials/disertationwriting/Writing%20&%20editing%20strategies%20for%20Progress%20Review%20session.doc, consulted May 28, 2008 , Larousse dictionary (2005) El pequeño larousse ilustrado, D.F-México,
Pereira, S. and Rubena, L .(2006) Focus and reading, Caracas-Venezuela,
http://academic.cuesta.edu/acasupp/as/308.HTM
Pereira, S. and Rubena, L .(2006) Focus and reading, Caracas-Venezuela,
http://academic.cuesta.edu/acasupp/as/308.HTM
Pre-reading:
The strategies used in pre-reading help students assess what prior knowledge they have of the content being taught and establish their purpose for reading.
Some examples of pre-reading strategies include: Predicting, skimmin, reading title and section headings, identifying what prior knowledge one has on the topic, learning important vocabulary words. The importance of pre-reading is that the reader developes motivation and backround knowledge about the subject matter of the text, also, generates a general idea of the text for better comprehension during the reading.
Post-reading:
Post-reading strategies help students deepen their understanding of the content, build further connections, and expand their prior knowledge of the subject matter.
Some examples of post-reading strategies include: Rereading, evaluating whether the purpose for reading was met, confirming predictions, summarizing, reflecting, questioning, thinking about how the material connects to one’s own life. Post reading also can determine if the predicting or the general idea made on the pre-reading was correct and if it was not the reader can understand the real purpose of the text and know which was the mistake done. It is also important to make the exercises proposed at the end of the text because by answering those questions the reader organizes and synthesizes the information in order to remember it.
http://departments.weber.edu/teachall/reading/post.html
http://wps.ablongman.com/ab_peregoy_esl_4/22/5725/1465732.cw/index.html
Skimming:
Is used to quickly identify the main ideas of a text. When you read the newspaper, you're probably not reading it word-by-word, instead you're scanning the text. Skimming is done at a speed three to four times faster than normal reading. People often skim when they have lots of material to read in a limited amount of time. Use skimming when you want to see if an article may be of interest in your research.
How to skim:
- Start at the beginning of the chapter and read the section headings.
- Think how the section headings flow from one to another and how they link with each other.
- Take note of vocabulary or terms, which may be in bold, or italics print.
- Read each topic sentence, usually the first sentence under the heading.
- Read the study questions at the end of the chapter and think: "Which section could I find that answer in?
- Go back and read each section.
Scanning:
Is a technique you often use when looking up a word in the telephone book or dictionary. You search for key words or ideas. In most cases, you know what you're looking for, so you're concentrating on finding a particular answer. Scanning involves moving your eyes quickly down the page seeking specific words and phrases. Scanning is also used when you first find a resource to determine whether it will answer your questions. Once you've scanned the document, you might go back and skim it.
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