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User:Marshallsumter/Radiation astronomy2/Visuals

What is “the “old-fashioned” spirit of real-time visual astronomy”? “I think everyone can conjure up a mental image of astronomers at every level and place in history, gazing through the eyepieces of their telescopes at sights far away - true visual astronomy.”

Radiation
White is the color of fresh milk and snow. It is the color the human eye sees when it looks at light which contains all the wavelengths of the visible spectrum, at full brightness and without absorption. It does not have any hue.

"de la couleur de la neige, du lait. Lumiere resultant de la combinaison de toutes les couleurs du spectre solaire." (of the color of snow, of milk. Light resulting from the combination of all the colors of the solar spectrum.)

Lights
Def. the "natural medium emanating from the sun and other very hot sources (now recognised as electromagnetic radiation with a wavelength of 400-750 nm), within which vision is possible" is called light.

Def. "to shine light" "on something" is called illuminate.

Fluorescences
Fluorescence is the emission of light by a substance that has absorbed light or other electromagnetic radiation. It is a form of luminescence. In most cases, the emitted light has a longer wavelength, and therefore lower energy, than the absorbed radiation. However, when the absorbed electromagnetic radiation is intense, it is possible for one electron to absorb two photons; this two-photon absorption can lead to emission of radiation having a shorter wavelength than the absorbed radiation. The emitted radiation may also be of the same wavelength as the absorbed radiation, termed "resonance fluorescence".

The most striking examples of fluorescence occur when the absorbed radiation is in the ultraviolet region of the spectrum, and thus invisible to the human eye, and the emitted light is in the visible region.

The common fluorescent lamp relies on fluorescence. Inside the glass tube is a partial vacuum and a small amount of mercury. An electric discharge in the tube causes the mercury atoms to emit ultraviolet light. The tube is lined with a coating of a fluorescent material, called the phosphor, which absorbs the ultraviolet and re-emits visible light. Fluorescent lighting is more energy-efficient than incandescent lighting elements. However, the uneven spectrum of traditional fluorescent lamps may cause certain colors to appear different than when illuminated by incandescent light or daylight. The mercury vapor emission spectrum is dominated by a short-wave UV line at 254 nm (which provides most of the energy to the phosphors), accompanied by visible light emission at 436 nm (blue), 546 nm (green) and 579 nm (yellow-orange). These three lines can be observed superimposed on the white continuum using a hand spectroscope, for light emitted by the usual white fluorescent tubes. These same visible lines, accompanied by the emission lines of trivalent europium and trivalent terbium, and further accompanied by the emission continuum of divalent europium in the blue region, comprise the more discontinuous light emission of the modern trichromatic phosphor systems used in many compact fluorescent lamp and traditional lamps where better color rendition is a goal.

Luminosities
J03.13 is the seventh extragalactic gravitational lens candidate to be discovered at the European Southern Observatory (ESO, La Silla). Its visual magnitude is 17.2 and the redshift is 2.545, corresponding to a distance of about 10 billion light-years. At the upper left (A) is the directly observed image of J03.13, as seen on a CCD frame with 3 min exposure and taken in red light (R-filter) with the [Superb-Seeing Imager] SUSI direct camera attached to the ESO New Technology Telescope (NTT) in February 1994. It clearly reveals the elongated shape, caused by the superposition of two images very near each other. In (B), the stronger of the two has been subtracted with an advanced image processing algorithm, based on the scaling of stellar profiles elsewhere in the frame. In (C), the fainter component has been removed, and in (D) the subtraction of both leaves no residual, indicating that there are no further detectable components of the quasar image. The intensity ratio between the two images is 1:7.

Def. emitting "light; glowing brightly" is called luminous.

Def. "the measure of the power of light as perceived by the human eye, in proportion to the power at each wavelength" is called luminous flux.

Def. the measure of the total power of electromagnetic radiation is called radiant flux, or radiant power.

Limiting the electromagnetic radiation to the visible may be called the apparent radiant flux.

Def. a "measure of the power emitted by a source of light; equal to the flux density per solid angle" is called luminous intensity.

Def. the "radiant energy of the visible portion of a spectrum of light" is called luminous energy.

Def. a "derived SI unit of luminous energy" is called a lumen second, or lumen-second.

Def. the total amount of visual, or visible light only electromagnetic energy emitted by a star or other astronomical object in SI units of joules per second, which are watts is called apparent luminosity.

Def. "the state of being luminous or a luminous object", "the ratio of luminous flux to radiant flux at the same wavelength", or "the rate at which a star radiates energy in all directions" is called luminosity.

Def. the rate at which a star radiates energy in all directions is called astronomical luminosity.

Skies
The overall theory of visual astronomy consists of three fundamental parts:
 * 1) the derivation of visual logical laws,
 * 2) the definitions of visual natural entities, and
 * 3) the definition of the visual sky (and associated realms).

Def. a visual or visible "expanse of space that seems to be [overhead] like a dome" is called a  visual sky, or visible sky.

Even in day light, the sky may seem absent of objects if a nearby source tends to overwhelm other luminous objects.

Naked eye astronomy
The visibility of astronomical objects is strongly affected by light pollution. Even a few hundred kilometers away from a metropolitan area where the sky can appear to be very dark, it is still the residual light pollution that sets the limit on the visibility of faint objects. For most people, this is likely to be the best observing conditions within their reach. Under such "typical" dark sky conditions, the naked eye can see stars with an apparent magnitude up to +6m. Under perfect dark sky conditions where all light pollution is absent, stars as faint as +8m might be visible. The angular resolution of the naked eye is about 1′; however, some people have sharper vision than that. There is anecdotal evidence that people had seen the Galilean moons of Jupiter before telescopes were invented. Of similar magnitude, Uranus and Vesta had most probably been seen but could not be recognized as planets because they appear so faint even at maximum brightness that their motion could not be detected.

"According to Gruson and Brugsch the Egyptians were acquainted with, and even worshipped, the zodiacal light from the very earliest times, as a phenomenon visible throughout the East before sunrise and after sunset. It was described as a glowing sheaf or luminous pyramid perpendicular to the horizon in summer, and inclined more or less during the winter. Indeed the Egyptians represented the zodiacal light under the form of a triangle which sometimes stood upright and at other times was inclined."

Whites
The white cliffs shown in the image at right are made of chalk, or calcium carbonate.

White light reflected off objects can be seen when no part of the light spectrum is reflected significantly more than any other and the reflecting material has a degree of diffusion. People see this when transparent fibers, particles, or droplets are in a transparent matrix of a substantially different refractive index. Examples include classic "white" substances such as sugar, foam, pure sand or snow, cotton, clouds, and milk. Crystal boundaries and imperfections can also make otherwise transparent materials white, as in the milky quartz or the microcrystalline structure of a seashell.

Cumulus clouds look white because the water droplets reflect and scatter the sunlight without absorbing other colors.

White light is generated by the sun, by stars, or by earthbound sources such as incandescent lamps, fluorescent lamps and white LEDs.

Blacks
Black is the color of coal, ebony, and of outer space. It is the darkest color, the result of the absence of or complete absorption of light. It is the opposite of white and often represents darkness in contrast with light.

"Opposite to white: colourless from the absence or complete absorption of light. Also, so near this as to have no distinguishable colour, very dark."

Black is "[t]he darkest color".

"Se dit de la couleur la plus foncée, due à l'absence ou à l'absorption totale des rayons lumineux." ("said of the very darkest color, due to the absence or complete absorption of all rays of light.")

Grays
Grey or gray is an intermediate color between black and white, a neutral or achromatic color, meaning literally a color "without color." It is the color of a cloud-covered sky, of wood ash and of lead.

The first image at right shows some red pebbles among gray pebbles, which are all the same rock type.

The first image at left shows the various shades of grey.

The second image at left of gray clay shows the cracking from water loss.

Albedos
Def. the fraction of incident light or radiation reflected by a surface or body, commonly expressed as percentage is called albedo.

Albedo, or reflection coefficient, derived from Latin albedo "whiteness" (or reflected sunlight), in turn from albus "white", is the diffuse reflectivity or reflecting power of a surface. It is defined as the ratio of reflected radiation from the surface to incident radiation upon it. Being a dimensionless fraction, it may also be expressed as a percentage, and is measured on a scale from zero for no reflecting power of a perfectly black surface, to 1 for perfect reflection of a white surface.

Albedo depends on the frequency of the radiation. When quoted unqualified, it usually refers to some appropriate average across the spectrum of visible light. In general, the albedo depends on the directional distribution of incoming radiation. Exceptions are Lambertian surfaces, which scatter radiation in all directions according to a cosine function, so their albedo does not depend on the incident distribution. In practice, a bidirectional reflectance distribution function (BRDF) may be required to characterize the scattering properties of a surface accurately, although the albedo is a very useful first approximation.

Albedos of typical materials in visible light range from up to 0.9 for fresh snow, to about 0.04 for charcoal, one of the darkest substances. Deeply shadowed cavities can achieve an effective albedo approaching the zero of a black body. When seen from a distance, the ocean surface has a low albedo, as do most forests, whereas desert areas have some of the highest albedos among landforms. Most land areas are in an albedo range of 0.1 to 0.4. The average albedo of the Earth is about 0.3. This is far higher than for the ocean primarily because of the contribution of clouds.

Two common albedos that are used in astronomy are the (V-band) geometric albedo (measuring brightness when illumination comes from directly behind the observer) and the Bond albedo (measuring total proportion of electromagnetic energy reflected). Their values can differ significantly.

Minerals
Beryl of various colors is found most commonly in granitic pegmatites, but also occurs in mica schists. Goshenite [a beryl clear to white cyclosilicate] is found to some extent in almost all beryl localities.

Quartzite (from German Quarzit ) is a hard, non-foliated metamorphic rock which was originally pure quartz sandstone. Sandstone is converted into quartzite through heating and pressure usually related to tectonic compression within orogenic belts. Pure quartzite is usually white to gray, though quartzites often occur in various shades of pink and red due to varying amounts of iron oxide (Fe2O3). Other colors, such as yellow and orange, are due to other mineral impurities.

The great majority of silicates are oxides which comprise the majority of the earth's crust, as well as the other terrestrial planets, rocky moons, and asteroids. Sand, Portland cement, and thousands of minerals are examples of silicates.

Mineralogically, silicate minerals are divided according to structure of their silicate anion into the following groups:

 * Nesosilicates (lone tetrahedron) - [SiO4]4−, e.g. olivine, tephroite.
 * Sorosilicates (double tetrahedra) - [Si2O7]6−, e.g. epidote, melilite group, leucophanite.
 * Cyclosilicates (rings) - [SinO3n]2n−, e.g. tourmaline group.
 * Inosilicates (single chain) - [SinO3n]2n−, e.g. pyroxene group.
 * Inosilicates(double chain) - [Si4nO11n]6n−, e.g. amphibole group.
 * Phyllosilicates (sheets) - [Si2nO5n]2n−, e.g. micas and clays like Kaolin.
 * Tectosilicates (3D framework) - [AlxSiyO2(x+y)]x−, e.g. quartz, feldspars, zeolites.

Visions
At right are normalized absorption spectra of the three human photopsins and of human rhodopsin.

Iodopsins ... are the photoreceptor proteins found in the cone cells of the [human] retina that are the basis of color vision. Iodopsins are very close analogs of the visual purple rhodopsin [R] that is used in night vision. Iodopsins consist of a protein called photopsin and a bound chromophore, retinal.

In humans there are three different iodopsins (rhodopsin analogs) that form the protein-pigment complexes photopsin I, II, and III. They are called erythrolabe, chlorolabe, and cyanolabe, respectively. These photopsins have absorption maxima for yellowish-green (photopsin I), green (photopsin II), and bluish-violet light (photopsin III).

Color indexes
"[T]he [visual] color index is a simple numerical expression that determines the color of an object, which in the case of a star gives its temperature. To measure the [visual] index, one observes the magnitude of an object successively through two different filters, such as ... B and V, where ... B is sensitive to blue light, and V is sensitive to visible (green-yellow) light ... The difference in magnitudes found with these filters is called the ... B–V color index ... The smaller the color index, the more blue (or hotter) the object is. Conversely, the larger the color index, the more red (or cooler) the object is. ... For comparison, the yellowish Sun has a B–V index of 0.656 ± 0.005, while the bluish Rigel has a B–V of –0.03 (its B magnitude is 0.09 and its V magnitude is 0.12, B–V = –0.03).

Color indices of distant objects are usually affected by interstellar extinction —i.e. they are redder than those of closer stars. The amount of reddening is characterized by color excess, defined as the difference between the Observed color index and the Normal color index (or Intrinsic color index), the hypothetical true color index of the star, unaffected by extinction. For example, we can write it for the B-V color:
 * $$E_{B-V} = (B-V)_{\textrm{Observed}} - (B-V)_{\textrm{Intrinsic}}$$

Visible bands
Molecules of "[l]arge polycyclic aromatic hydrocarbons (PAH) ... or their ions are also attractive candidates for the carriers of the diffuse interstellar bands in the visible (DIBs) [because]
 * 1) they have optically active transitions in the visible;
 * 2) they can survive the UV photons in the diffuse interstellar medium; [and]
 * 3) they are the most abundant among the detected molecular species after H2 and CO."

Visible spectrum
The visible spectrum is the portion of the electromagnetic spectrum that is visible to (can be detected by) the human eye. Electromagnetic radiation in this range of wavelengths is called visible light or simply light. A typical human eye will respond to wavelengths from about 390 to 750 nm. In terms of frequency, this corresponds to a band in the vicinity of 400–790 THz. A light-adapted eye generally has its maximum sensitivity at around 555 nm (540 THz), in the green region of the optical spectrum (see: luminosity function).

Below are the visible emission spectra from the first eight elements of the periodic table.

Theoretical visual astronomy
Def. the ratio of the flux reflected to that incident on a surface is called a reflectance.

According to the CIE (the International Commission on Illumination), reflectivity is distinguished from reflectance by the fact that reflectivity is a value that applies to thick reflecting objects. When reflection occurs from thin layers of material, internal reflection effects can cause the reflectance to vary with surface thickness. Reflectivity is the limit value of reflectance as the sample becomes thick; it is the intrinsic reflectance of the surface, hence irrespective of other parameters such as the reflectance of the rear surface. Another way to interpret this is that the reflectance is the fraction of electromagnetic power reflected from a specific sample, while reflectivity is a property of the material itself, which would be measured on a perfect machine if the material filled half of all space.

Specular reflection is the mirror-like reflection of light (or of other kinds of wave) from a surface, in which light from a single incoming direction (a ray) is reflected into a single outgoing direction.

Specular reflection is distinct from diffuse reflection, where incoming light is reflected in a broad range of directions.

Def. the condition of being specular, or the degree to which something is specular is called specularity.

Specularity refers the smoothness of a surface. A highly specular surface is very smooth.

It has been shown that for many applications involving terrestrial albedo, the albedo at a particular solar zenith angle $${\theta_i}$$ can reasonably be approximated by the proportionate sum of two terms: the directional-hemispherical reflectance at that solar zenith angle, $${\bar \alpha(\theta_i)}$$, and the bi-hemispherical reflectance, $$\bar{ \bar \alpha}$$ the proportion concerned being defined as the proportion of diffuse illumination $${D}$$. Bold added.

Albedo $${\alpha}$$ may be given by:

 * $${\alpha}= (1-D) \bar \alpha(\theta_i) + D \bar{ \bar \alpha}.$$

Directional-hemispherical reflectance is sometimes referred to as black-sky albedo and bi-hemispherical reflectance as white-sky albedo. These terms are important because they allow the albedo to be calculated for any given illumination conditions from a knowledge of the intrinsic properties of the surface.

In detailed studies, the directional reflectance properties of astronomical bodies are often expressed in terms of the five Hapke parameters which semi-empirically describe the variation of albedo with phase angle, including a characterization of the opposition effect of regolith surfaces.

The correlation between astronomical (geometric) albedo, absolute magnitude and diameter is:

$$A =\left ( \frac{1329\times10^{-H/5}}{D} \right ) ^2,$$

where $$A$$ is the astronomical albedo, $$D$$ is the diameter in kilometers, and $$H$$ is the absolute magnitude.

Continua
Black and white images are not ordinarily starkly contrasted black and white but combine black and white in a continuum producing a range of shades of gray.

In physics, a continuous spectrum usually means a set of values for some physical quantity (such as energy or wavelength) that is best described as an interval of real numbers. It is opposed to discrete spectrum, a set of values that is discrete in the mathematical sense, where there is a positive gap between each value and the next one.

At left is a continuous spectrum from a deuterium lamp. The tall sharp peaks are discrete emissions and the continuous part is the smoothly varying part between the peaks. The smaller peaks and valleys may be due to measurement errors rather than discrete spectral lines.

"[W]ith Scorpius X-1 ... the visible continuum is roughly what would be expected from a hot plasma fitting the observed X-ray flux. The plasma could be a coronal cloud of a central object or a transient plasma, where the energy source is unknown, but could be related to the idea of a close binary.

A spectrum (plural spectra or spectrums ) is a condition that is not limited to a specific set of values but can vary infinitely within a continuum.

In the continuum of colors of visible light [green] is located between yellow and blue.

Continuum light is linearly polarized at different locations across the face of the Sun (limb polarization) though taken as a whole, this polarization cancels.

In optics, a supercontinuum is formed when a collection of nonlinear processes act together upon a pump beam in order to cause severe spectral broadening of the original pump beam. The result is a smooth spectral continuum.

The figure at right shows a typical supercontinuum spectrum about an emission-line source. The blue line shows the spectrum of the source launched into a photonic crystal fiber while the red line shows the resulting supercontinuum spectrum generated after propagating through the fiber.

The inverse Raman effect in optics ... which deals with the properties and behavior of light) is a form of Raman scattering.

If a material is simultaneously irradiated by intense monochromatic light of frequency νL (typically a laser beam) and light of a continuum of higher frequencies, among the possibilities for light scattering are scattering:

 * from the monochromatic beam at νL to the continuum at νL+νM (anti-Stokes Raman scattering)
 * from the continuum at νL+νM to the monochromatic beam at νL (Stokes Raman scattering)

where νM is a Raman frequency of the material.

The strength of these two scatterings depends (among other things) on the energy levels of the material, their occupancy, and the intensity of the continuum. In some circumstances Stokes scattering can exceed anti-Stokes scattering; in these cases the continuum (on leaving the material) is observed to have an absorption line (a dip in intensity) at νL+νM. This phenomenon is referred to as the inverse Raman effect; the application of the phenomenon is referred to as inverse Raman spectroscopy, and a record of the continuum is referred to as an inverse Raman spectrum.

Both absorption from a continuum of higher frequencies and absorption from a continuum of lower frequencies [can occur]. Absorption from a continuum of lower frequencies will not be observed if the Raman frequency of the material is vibrational in origin and if the material is in thermal equilibrium.

Reverberation mapping is an astrophysical technique for measuring the structure of the broad emission-line region (BLR) around a supermassive black hole at the center of an active galaxy and estimating the hole's mass. It is considered a "primary" mass estimation technique, i.e., the mass is measured directly from the motion that its gravitational force induces in the nearby gas.

The black hole mass is measured from the formula

GM_\bullet = f R_\mathrm{BLR} (\Delta V)^2. $$

In this formula, ΔV is the rms velocity of gas moving near the black hole in the broad emission-line region, measured from the Doppler broadening of the gaseous emission lines; RBLR is the radius of the broad-line region; G is the constant of gravitation; and f is a poorly-known "form factor" that depends on the shape of the BLR.

The biggest difficulty with applying this formula is the measurement of RBLR. One standard technique is based on the fact that the emission-line fluxes vary strongly in response to changes in the continuum, i.e., the light from the accretion disk near the black hole ("reverberation"). Furthermore, the emission-line response is found to be delayed with respect to changes in the continuum. Assuming that the delay is due to light travel times, the size of the broad emission-line region can be measured.

Only a small handful of AGN (less than 40) have been accurately "mapped" in this way. An alternative approach is to use an empirical correlation between RBLR and he continuum luminosity.

Another uncertainty is the value of f. In principle, the response of the BLR to variations in the continuum could be used to map out the three-dimensional structure of the BLR. In practice, the amount and quality of data required to carry out such a deconvolution is prohibitive. Until about 2004, f was estimated ab initio based on simple models for the structure of the BLR. More recently, the value of f has been determined so as to bring the M-sigma relation for active galaxies into the best possible agreement with the M-sigma relation for quiescent galaxies. When f is determined in this way, reverberation mapping becomes a "secondary", rather than "primary," mass estimation technique.

Backgrounds
The diffuse extragalactic background light (EBL) is all the accumulated radiation in the Universe due to star formation processes, plus a contribution from active galactic nuclei (AGNs). This radiation covers the wavelength range between ~ 0.1-1000 microns (these are the ultraviolet, optical, and infrared regions of the electromagnetic spectrum). The EBL is part of the diffuse extragalactic background radiation (DEBRA), which by definition covers the overall electromagnetic spectrum. After the cosmic microwave background, the EBL produces the second-most energetic diffuse background, thus being essential for understanding the full energy balance of the universe.

The observed radiation density (the sky brightness of extragalactic background light) can be independent of finiteness of the Universe.

In astronomy, background commonly refers to the incoming light from an apparently empty part of the night sky.

In astronomy, background noise is electromagnetic radiation from the sky with no discernible source.

Even if no visible astronomical objects are present in given part of the sky, there always is some low luminosity present, due mostly to light diffusion from the atmosphere (diffusion of both incoming light from nearby sources, and of man-made Earth sources like cities). In the visible band, luminosity level is around the 22nd magnitude per square-arcsecond: a very low level, but anyway well within the limits of the current generation of telescopes.

There are several sources which contribute to the brightness of the (night) sky. Some of these are instrumental, or due to the presence of the atmosphere (like the airglow), in the case of ground based instruments. Even if we able to minimize the effect of instrumental and atmospherical components (e.g. using a spacecraft), there are still several astrophysical components contributing to the sky background: these could be sets of point sources like faint asteroids, Galactic stars and far away galaxies, as well as diffuse sources like dust in the Solar System, in the Milky Way, and in the intergalactic space. The actual importance of a specific component depends mostly of the wavelength of the measurement. The uncertainty (or noise) of the measurements caused by the astrophysical components of the sky background is called confusion noise.

Visual snow is a transitory or persisting snow or television-like static in parts or the whole of [the] visual fields, especially against dark backgrounds. It is much like camera noise in low light conditions. The visual frame at right shows an example of visual snow.

In astronomical CCD technology, background is usually referred to the overall optical "noise" of the system, that is, the incoming light on the CCD sensor in absence of light sources. This background can originate from electronic noise in the CCD, from not-well-masked lights nearby the telescope, and so on. An exposure on an empty patch of the sky is also called a background, and is the sum of the system background level plus the sky's one.

A background frame is often the first exposure in an astronomical observation with a CCD: the frame will then be subtracted from the actual observation result, leaving in theory only the incoming light from the astronomical object being observed.

Hydrogens
The Balmer series of emission lines from hydrogen occur in the visible spectrum of the Sun at: 397, 410, 434, 486, and 656 nm. Hα is the red line at the far right.

Helium
Helium was first detected as an unknown yellow spectral line signature in sunlight during a solar eclipse in 1868 by French astronomer Jules Janssen. Janssen is jointly credited with detecting the element along with Norman Lockyer during the solar eclipse of 1868, and Lockyer was the first to propose that the line was due to a new element, which he named.

Lithiums
"Violet satellite bands are caused by those lithium atoms which undergo an optical transition while a helium atom is nearby."

Lithium I has an orange line at 610.3 nm. In some 824 red giant stars, the Li I 670.78 nm line was detected in several stars, "but only the five objects ... presented a strong line. Indeed, the Li subordinate line at 6103.6 Å was detected in these stars only."

Berylliums
The visual spectrum for beryllium is missing characteristic lines in the yellow and orange.

Borons
Similar to beryllium, the visual spectrum of boron is missing lines in the yellow, but unlike it is also missing lines in the green and has a line in the orange.

Carbons
There is a C2 band at 619.1 nm. Sometimes there is a hint of 13C12C at 618.8 nm.

Carbon has a representative line in each of the major visual colors.

Nitrogens
"[T]he 5198-, 5201-A lines of nitrogen [occur] in the [Earth's] nightglow."

Oxygens
"[A]irglow emissions [have been] measured by using vertical-viewing photometers [for the] O(1S) green line at 557.7 nm [with a] background at 566 nm".

Fluorine
Fluorine has green emission lines that occur in plasmas at 526.83, 528.56, 529.76 and 530.27 nm from F VI.

Fluorine has two emission lines that occur in plasmas at 479.132 and 479.45 nm from F IX.

Fluorine has an emission line that occurs in plasmas at 429.92 nm from F II.

Neon
There is a "bright yellow line of neon X [at] 5852.488 [Å, 585.2488 nm.]"

Neon has two emission lines at 614.3 and 616.3 nm from Ne I.

Absorption lines
Fraunhofer's original (1817) designations of absorption lines in the solar spectrum

Fraunhofer line 'A' is an optical astronomy absorption line, not a visual astronomy absorption line.

Planetary sciences
"The Weaubleau structure is a probable meteorite impact site in western Missouri near the towns of Gerster, Iconium, Osceola, and Vista. It is believed to have been caused by a 1200-ft (366 m) meteoroid between 330 and 335 million years ago during the late Mississippian Period (Latest Osagean to Earliest Meramecian). It is listed by the Impact Field Studies Group as a "probable" impact structure.

The structure consists of an area of severe structural deformity and extensive brecciation that was poorly understood and had been thought to be the result of either thrusting over a dome or a cryptoexplosive event. A 19-km-diameter (12 mi) circular structure was discovered ... through examination of digital elevation data.

Because the site was covered by later Pennsylvanian Period sediments, and only partially exposed to erosion relatively recently, its structure is well preserved, and its age can be determined with fair accuracy. It is one of a series of known or suspected impact sites along the 38th parallel in the states of Illinois, Missouri, and Kansas.

The Weaubleau structure is one of the fifty largest known impact craters on earth and the fourth largest in the United States. The three larger ones in the US either have been glaciated and buried (Manson crater), are under water (Chesapeake Bay crater), or have been subjected to orogeny (Beaverhead crater). Therefore the Weaubleau structure is the largest exposed untectonized impact crater in the US.

Meteors
Meteors become visible between about 75 to 120 kilometers (34 - 70 miles) above the Earth. They disintegrate at altitudes of 50 to 95 kilometers (31-51 miles). Most meteors are observed at night, when darkness allows fainter objects to be recognized. Most meteors glow for about a second.

A fireball is a brighter-than-usual meteor. The International Astronomical Union defines a fireball as "a meteor brighter than any of the planets" (magnitude −4 or greater). The International Meteor Organization (an amateur organization that studies meteors) has a more rigid definition. It defines a fireball as a meteor that would have a magnitude of −3 or brighter if seen at zenith. This definition corrects for the greater distance between an observer and a meteor near the horizon. For example, a meteor of magnitude −1 at 5 degrees above the horizon would be classified as a fireball because if the observer had been directly below the meteor it would have appeared as magnitude −6. For 2011 there are 4589 fireballs records at the American Meteor Society.

Def. a fireball reaching magnitude −14 or brighter. is called a bolide.

Def. a fireball reaching an magnitude −17 or brighter is called a superbolide.

At right is a cell phone camera image of the green fireball over San Mateo, California, that left meteorite fragments. "The asteroid entered at a speed of 14 km/s, typical but on the slow side of other meteorite falls for which orbits were determined. ... The orbit in space is also rather typical: perihelion distance close to Earth's orbit (q = 0.987 AU) and a low-inclination orbit (about 5 degrees). ... 2012, October 17 - At 7:44:29 pm PDT this evening, a bright fireball was seen in the San Francisco Bay Area."

Venus
In visual astronomy almost no variation or detail can be seen in the clouds. The surface is obscured by a thick blanket of clouds. Venus is shrouded by an opaque layer of highly reflective clouds of sulfuric acid, preventing its surface from being seen from space in visible light. It has thick clouds of sulfur dioxide. There are lower and middle cloud layers. The thick clouds consisting mainly of sulfur dioxide and sulfuric acid droplets. These clouds reflect and scatter about 90% of the sunlight that falls on them back into space, and prevent visual observation of the Venusian surface. The permanent cloud cover means that although Venus is closer than Earth to the Sun, the Venusian surface is not as well lit.

Earth
The average overall albedo of Earth, its planetary albedo, is 30 to 35%, because of the covering by clouds, but varies widely locally across the surface, depending on the geological and environmental features.

Although the albedo–temperature effect is best known in colder, whiter regions on Earth, the maximum albedo is actually found in the tropics where year-round illumination is greater. The maximum is additionally in the northern hemisphere, varying between 3 and 12 degrees north. The minima are found in the subtropical regions of the northern and southern hemispheres, beyond which albedo increases without respect to illumination.

Deciduous trees have an albedo value of about 0.15 to 0.18 whereas coniferous trees have a value of about 0.09 to 0.15.

The relative (generally warming) effect of albedo change and (cooling) effect of carbon sequestration on planting forests indicates that new forests in tropical and midlatitude areas tended to cool; new forests in high latitudes (e.g. Siberia) were neutral or perhaps warming.

Cryoconite, powdery windblown dust containing soot, sometimes reduces albedo on glaciers and ice sheets.

At small angles of incident light, waviness [of water] results in reduced reflectivity because of the steepness of the reflectivity-vs.-incident-angle curve and a locally increased average incident angle.

"On any given day, about half of Earth is covered by clouds, which reflect more sunlight than land and water. Clouds keep Earth cool by reflecting sunlight, but they can also serve as blankets to trap warmth."

As the second image on the right shows, specular reflection, or reflectance, occurs on Earth.

Moon
The overall albedo of the Moon is around 0.12, but it is strongly directional and non-Lambertian, displaying also a strong opposition effect.

Mars
"This is the south polar cap of Mars as it appeared to the Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) on April 17, 2000. In winter and early spring, this entire scene would be covered by frost. In summer, the cap shrinks to its minimum size, as shown here. Even though it is summer, observations made by the Viking orbiters in the 1970s showed that the south polar cap remains cold enough that the polar frost (seen here as white) consists of carbon dioxide. Carbon dioxide freezes at temperatures around -125° C (-193° F). Mid-summer afternoon sunlight illuminates this scene from the upper left from about 11.2° above the horizon. Soon the cap will experience sunsets; by June 2000, this pole will be in autumn, and the area covered by frost will begin to grow. Winter will return to the south polar region in December 2000. The polar cap from left to right is about 420 km (260 mi) across."

Enceladus
At right is Saturn's natural satellite, the rocky object, Enceladus.

Enceladus, a moon of Saturn, has one of the highest known albedos of any body in the Solar system, with 99% of EM radiation reflected.

"The Cassini spacecraft looks at a brightly illuminated Enceladus and examines the surface of the leading hemisphere of this Saturnian moon."

"North on Enceladus (313 miles across, or 504 kilometers) is up and rotated 21 degrees to the right."

"The image was taken in visible light with the Cassini spacecraft narrow-angle camera on Nov. 6, 2011. The view was obtained at a distance of approximately 67,700 miles (109,000 kilometers) from Enceladus and at a Sun-Enceladus-spacecraft, or phase, angle of 21 degrees. Image scale is 2,130 feet (649 meters) per pixel."

Comets
A typical comet nucleus has an albedo of 0.04.

At left is an image of Comet West. "Comet West was a stunning sight in the predawn sky of March, 1976, bright with a tall and broad dust tail. ... [T]he comet [was] discovered on photographs taken in August 1975 by Richard West of the European Southern Observatory ... Comet West passed perihelion on February 25, 1976, at a distance of 0.20 a.u. [and] had reached about magnitude -3 at perihelion. Several observers saw it telescopically in daylight, and John Bortle observed it with the naked eye shortly before sunset. ... The following morning, March 7, ... It was brilliant, with a head as bright as Vega (which was nearly overhead) and a huge tail, about 20 degrees tall, straight near the bottom and bending to the left in its upper reaches. The comet quickly faded during March".

Although many comets are photographed in black and white, not that many are actually only white but have colors. The image at right of McNaught Comet shows white and other colors, as does Comet West at left.

Eris
A notable high-albedo body is Eris, with an albedo of 0.96.

Opticals
In popular culture optical astronomy encompasses a wide variety of observations via telescopes that are sensitive in the range of visible light. Scientists would call this visible-light astronomy. It includes imaging, where a picture of some sort is made of the object; photometry, where the amount of light coming from an object is measured, spectroscopy, where the distribution of that light with respect to its wavelength is measured, and polarimetry where the polarisation state of that light is measured.

Violets
Violet astronomy is conducted over wavelengths between 380 and 450 nm.

Violet photographs of the planet Venus taken in 1927 “recorded two nebulous bright streaks, or bands, running ... approximately at right angles to the terminator” that may be from the upper atmosphere.

"A definite color gradient is observed [in the small inner satellites of Jupiter], with the satellites closer to Jupiter being redder: the mean violet/green ratio (0.42/0.56 μm) decreases from Thebe to Metis. This ratio also is lower for the trailing sides of Thebe and Amalthea than for their leading sides."

"The “Purple Haze” is a diffuse blueish/purple glow within a few arcseconds of the central star in HST images of the Homunculus (Morse et al. 1998; Smith et al. 2000, 2004). This emission is seen in excess of violet starlight scattered by dust, and the strength of the excess increases into the far UV (Smith et al. 2004; hereafter Paper I)."

Blues
Blue is the wavelength range 450-475 nm.

A trace amount of methane is also present. Prominent absorption bands of methane occur at wavelengths above 600 nm, in the red and infrared portion of the spectrum. As with Uranus, this absorption of red light by the atmospheric methane is part of what gives Neptune its blue hue, although Neptune's vivid azure differs from Uranus's milder cyan. Since Neptune's atmospheric methane content is similar to that of Uranus, some unknown atmospheric constituent is thought to contribute to Neptune's colour.

Stars are often referred to by their predominant color. For example, blue stragglers are found among the galactic halo globular clusters. Blue main sequence stars that are metal poor ([Fe/H] ≤ -1.0) are most likely not analogous to blue stragglers.

"The Algol-type binaries are close, semi-detached, interacting binary star systems which contain a cool F–K giant or sub-giant secondary star that fills its Roche lobe and is losing mass to a hot B–A main sequence primary star."

"The Algols contain a hot blue dwarf star with a magnetically-active late-type companion. In the close Algols, the gas stream flows directly into the photosphere of the blue mass-gaining star because it does not have enough room to avoid impact with that star."

"[G]round-based UV [and blue astronomy] is a powerful facility for [the] study of [the] chemical evolution of [the] early Galaxy." The UV and B astronomy are over the wavelength range 355.0-500.0 nm.

Cyans
Cyan astronomy focuses on the wavelength range 476-495 nm.

Electric blue is a color close to cyan that is a representation of the color of lightning, an electric spark, and argon signs.

The electric blue glow of electricity results from the spectral emission of the excited ionized atoms (or excited molecules) of air (mostly oxygen and nitrogen) falling back to unexcited states, which happens to produce an abundance of electric blue light. This is the reason electrical sparks in air, including lightning, appear electric blue. It is a coincidence that the color of Cherenkov radiation and light emitted by ionized air are a very similar blue despite their very different methods of production.

Both Luna 24 and Apollo 12 soil samples are from mare soils that reflect primarily cyan that is likely due to the presence of TiO2 in the soils.

"Previous work has suggested that a cyan color in the multispectral frame represents highland material, and that yellows and greens are freshly excavated basalts. However, we have recently found that a cyan color can also result from a freshly excavated high-Ti basalt."

In larger amateur telescopes with an objective diameter of between 15 and 23 cm, the planet appears as a pale cyan disk with distinct limb darkening.

Methane possesses prominent absorption bands in the visible and near-infrared (IR) making Uranus aquamarine or cyan in color.

Greens
Green objects or emission lines in the green portion of the visible spectrum are the subject of green astronomy. "Carroll and McCormack (1972) in Dublin reported complex spectra in the blue and green wavelength regions of both FeH and FeD".

For elongated dust particles in cometary comas an investigation is performed at 535.0 nm (green) and 627.4 nm (red) peak transmission wavelengths of the Rosetta spacecraft's OSIRIS Wide Angle Camera broadband green and red filters, respectively. "In the green, the polarization of the pure silicate composition qualitatively appears a better fit to the shape of the observed polarization curves". "[B]ut they are characterized by a high albedo." The silicates used to model the cometary coma dust are olivene (Mg-rich is green) and the pyroxene, enstatite.

In December 2006, seven papers were published in the scientific journal, Science, discussing initial details of the sample analysis. Among the findings are: a wide range of organic compounds, including two that contain biologically usable nitrogen; indigenous aliphatic hydrocarbons with longer chain lengths than those observed in the diffuse interstellar medium; abundant amorphous silicates in addition to crystalline silicates such as olivine and pyroxene, proving consistency with the mixing of solar system and interstellar matter, previously deduced spectroscopically from ground observations; hydrous silicates and carbonate minerals were found to be absent, suggesting a lack of aqueous processing of the cometary dust; limited pure carbon (CHON) was also found in the samples returned; methylamine and ethylamine was found in the aerogel but was not associated with specific particles. In the image at right the iron (Fe XIV) green line is followed by doppler imaging to show associated relative coronal plasma velocity towards (-7 km/s side) and away from (+7 km/s side) the large angle spectrometric coronagraph LASCO satellite camera.

Yellows
There are yellow objects and emission lines in the yellow portion of the visible spectrum to introduce yellow astronomy.

During the limb flares of December 18, 1956, a coronal line at 569.4 nm, a yellow line, occurred at 1822 UTC, 1900 UTC, undiminished up to 20,000 km above the solar limb, and at 2226 UTC, is identified as Ca XV. "The coronal temperature was 4000000°." "The December 18, 1956, flare appears to have been a violent condensation of material from a dense coronal cloud above an active region."

The image at right shows several blue, loop-shaped objects that are multiple images of the same galaxy, duplicated by the gravitational lens effect of the cluster of yellow galaxies near the middle of the photograph. The lens is produced by the cluster's gravitational field that bends light to magnify and distort the image of a more distant object.

Oranges
“Orange light at the wavelength of 590 nm is composed of photons having energy of 2.0 eV.”

The Spite plateau (or Spite lithium plateau) is a baseline in the abundance of lithium found in old stars orbiting the galactic halo.

The curve on a graph of the abundance of lithium versus effective surface temperature formed a plateau among old halo stars for effective temperatures below about:
 * log Teff ~ 3.75

or roughly 5,600 K. This suggested that the plateau represented the primordial abundance level of lithium in the Milky Way ... [with an estimate] that the abundance of lithium at the beginning of the galaxy was:
 * NLi = (11.2 ± 3.8) × 10−11 NH

where NH is the abundance of hydrogen.

"Lithium depletion through atomic diffusion has been suggested as a solution to the discrepancy between the Spite plateau abundance and the predicted value of the primordial lithium abundance".

The orange system [in orange astronomy] is a number of emission lines very close together forming a band in the orange portion of the visible spectrum. These lines are usually associated with particular molecular species, including ScO, YO, and TiO.

The variability of BD +50 961 (SY Persei, an orange star) is confirmed.

Reds
With respect to the color 'red', there are studies of the 'red shift' and the redness of objects such as the red dwarf AZ Cancri shown in the visual image at right. Red is 620-750 nm.

"Ideally all intrinsic colours should be found from unreddened stars. This is possible for dwarf and giant stars later than about A0 (Johnson, 1964) ... However, it cannot be used for stars of other spectral classes since they are all relatively infrequent in space, and generally reddened."

Red supergiants (RSGs) are supergiant stars (luminosity class I) of spectral type K or M. They are the largest stars in the universe in terms of volume, although they are not the most massive. Betelgeuse and Antares are the best known examples of a red supergiant. These stars have very cool surface temperatures (3500–4500 K), and enormous radii. The five largest known red supergiants in the Galaxy are VY Canis Majoris, VV Cephei A, V354 Cephei, RW Cephei and KW Sagittarii, which all have radii about 1500 times that of the Sun (about 7 astronomical units, or 7 times as far as the Earth is from the Sun). The radius of most red giants is between 200 and 800 times that of the Sun. Absolute luminosities may reach -10 magnitude compared to +5 for our Sun.

Hypotheses

 * 1) Neptune was visible to visual astronomers within the last 40,000 years.


text:
User talk:Ananth-murali

 Hello Ananth-murali, and welcome to Wikiversity! If you need help, feel free to visit my talk page, or contact us and ask questions. After you leave a comment on a talk page, remember to sign and date; it helps everyone follow the threads of the discussion. The signature icon in the edit window makes it simple. All users are expected to abide by our Privacy policy, Civility policy, and the Terms of Use while at Wikiversity.

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license: Creative Commons - Attribution Share-Alike - https://creativecommons.org/licenses/by-sa/4.0/

title: User talk:Ananth-murali


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User:Johncnorth

My name is John... This is my user page.

title: User:Johncnorth


text:
User talk:Johncnorth

 Hello Johncnorth, and welcome to Wikiversity! If you need help, feel free to visit my talk page, or contact us and ask questions. After you leave a comment on a talk page, remember to sign and date; it helps everyone follow the threads of the discussion. The signature icon in the edit window makes it simple. All users are expected to abide by our Privacy policy, Civility policy, and the Terms of Use while at Wikiversity.

To get started, you may

 * Take a guided tour and learn to edit.
 * Visit a (kind of) random project.
 * Browse Wikiversity, or visit a portal corresponding to your educational level: pre-school, primary, secondary, tertiary, non-formal education.
 * Find out about research activities on Wikiversity.
 * Explore Wikiversity with the links to your left.

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You don't need to be an educator to edit. You only need to be bold to contribute and to experiment with the sandbox or your userpage. See you around Wikiversity! --Claritas 08:10, 9 January 2012 (UTC)

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text:
User:Zahmatkesh

Blood-Brain Barrier (BBB) The brain is protected by Harmful substances are shielded from the brain by the Blood-Brain Barrier.
 * Bone
 * Meninges
 * Cerebrospinal fluid

BBB is the most significant element responsible for the preservation of CNS homeostasis. Brain edema formation after stroke has been linked to the inability of the BBB to maintain necessary ion gradients. Alterations in BBB ion homeostasis have been linked with epilepsy. Changes in BBB function have been described in several neurological disorders, including stroke, multiple sclerosis and Alzheimer’s disease.In Alzheimer’s disease, β-amyloid induces cytokine release and monocyte migration across an in vitro BBB in vivo β-amyloid deposition leads to degeneration of the microvascular basement membrane and alterations in BBB permeability.

Development of the Blood-Brain Barrier The counterpart of this situation in later life is the syndrome, in which there is a congenital deficiency of glucuronyl transferase. These individuals can have very high free bilirubin levels in the blood and develop encephalopathy.
 * It is often stated that the BBB is immature at birth.
 * In severely jaundiced infants with high plasma levels of free bilirubin and an immature hepatic bilirubin-conjugating system, free bilirubin enters the brain and, in the presence of asphyxia, damages the basal ganglia (kernicterus).

Function of the blood-brain barrier
 * Controls delivering of nutrients to and removing metabolites from the CNS compartment.
 * It is a barrier for ionic currents and hydrophilic compounds able to cross it only through special membrane transporters.
 * The BBB regulates the ion balance of the brain. Brain edema after stroke has been linked to the inability of the BBB to maintain necessary ion gradients.
 * Protects the CNS from abrupt changes in blood biochemistry that occur after meals, physical excercises, or in pathological conditions.
 * BBB is an extremely important „guardian” that regulates access of drugs to the CNS under both physiological and pathological circumstances.
 * BBB components are responsible for the biochemical modification of chemicals that enter the CNS. Moreover, some drugs, even if they can cross the BBB, are immediately removed from the CNS.
 * Divides neurotransmitters and in general, neuroactive substances into two pools of Central & Peripheral systems

BBB building blocks: Endothelial cells Astrocytes Pericytes

Nanotechnology approaches to crossing the blood-brain barrier

title: User:Zahmatkesh


title: File:C.Repeat.Control.1.A.20120109.pdf


title: File:C.Repeat.Loop.1.A.20120109.pdf


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User:Areil314/sandbox

Sample topic page
{| class="wikitable" ! Header text !! Header text

Example
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title: User:Areil314/sandbox


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User:Areil314/sandbox/sample sub page

(from Controversies in Science)

Did life on Earth arise from Panspermia?

title: User:Areil314/sandbox/sample sub page


text:
User:Juandev (usurped)/Discovering Wikimedia Czech Republic

''This is a user preparation for the presenatation. You are welcome to discuss it on a talk page.''

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User:Areil314/sandbox/sample sub page/test2

test 2 page


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User:Marshallsumter/Radiation astronomy/First X-ray source in Apus

The first X-ray source in Apus discovered by our X-ray observatory satellites or rockets is unknown.

Above is a sky plot of the X-ray sources detected by the ROSAT all-sky survey in the Chamaeleon star-forming cloud complex. X-ray sources (Xs in the diagram) along the 14:00 h longitude are in the constellation Apus.

This is a lesson in map reading, coordinate matching, and researching. It is also a research project in the history of X-ray astronomy looking for the first astronomical X-ray source discovered in the constellation of Apus.

Nearly all the background you need to participate and learn by doing you've probably already been introduced to at a secondary educational level.

Some of the material and information you'll be introduced to is at the college or university level, and as you progress in finding X-ray sources, you'll run into concepts and experimental tests that are actual research.

To succeed in finding an X-ray source in Apus is the first step. Next, you'll need to determine the time stamp of its discovery and compare it with any that have already been found. Over the history of X-ray astronomy a number of sources have been found, many as point sources in the night sky. These points are located on the celestial sphere using coordinate systems. Familiarity with these coordinate systems is not a prerequisite. Here the challenge is geometrical, astrophysical, and historical.

Backgrounds
To introduce yourself to some aspects of the challenge may I suggest reading the highlighted links mentioned above, and if you're curious, those listed under the section "See also" below.

X-rays are a form of radiation that is part of the electromagnetic radiation intersecting the Earth. More information about radiation is in radiation astronomy.

Constellations
The Wikipedia article about the constellation Apus contains a high school level description. The figure at right shows the sky map of Apus. Around the edges of the map are coordinates related to longitude and latitude, but with the Earth rotating on its axis every 24 hours the celestial coordinates must remain fixed. How has this been accomplished?

Apus is a faint constellation in the southern sky, first defined in the late 16th century.

"Apus was one of twelve constellations created by Petrus Plancius from the observations of Pieter Dirkszoon Keyser and Frederick de Houtman and it first appeared on a 35 cm diameter celestial globe published in 1597 (or 1598) in Amsterdam by Plancius with Jodocus Hondius. Plancius called the constellation "Paradysvogel Apis Indica"; the first word is Dutch for 'bird of paradise,' of genus Pteridophora, but the others are Latin for "Indian Bee," although "apis" (Latin for "bee") is presumably an error for "avis" or "bird".

After its introduction on Plancius's globe, the first known depiction of the constellation in a celestial atlas was in Johann Bayer's Uranometria of 1603, where it was called "Apis Indica".

When the Ming Dynasty Chinese astronomer Xu Guangqi adapted the European southern hemisphere constellations to the Chinese system in The Southern Asterisms, he combined Apus with some of the stars in Octans to form the "Exotic Bird" (異雀, Yìquè).

The Sun is an X-ray source that travels through the 13 constellations along the ecliptic. Is Apus a constellation that the Sun travels through?

Also, in the Wikipedia article is a list of stars in Apus. What's the difference between a star and an astronomical X-ray source?

Testing a source
There are many web sites that may have an X-ray source listed for the constellation Apus.

Wikipedia sources
Under "Notable features" in the Wikipedia article on the constellation Apus is the list of stars in Apus. Click on this link. In the table of this Wikipedia article is α Aps. To the right are coordinates:
 * 1) Right ascension (RA): 14h 47m 51.73s and
 * 2) Declination (Dec): -79° 02' 41.0".

Find these coordinates on the Apus map at the right. Is alpha Apodis really inside the boundaries of the constellation?

To evaluate the star as an X-ray source, skip ahead to section "X-ray source".

Another Wikipedia source for stars in Apus is the "Template:Stars of Apus", which can be searched by entering "Template:Stars of Apus", without the quotes. Stars already searched may not have had their other designations updated in the template.

SIMBAD sources
Another way to find possible X-ray sources in Apus is to use other search queries on SIMBAD.

Click on the SIMBAD link under "External links" below, then click on "Criteria query".

In the tan box, type in "region(14 47 51.73 -79 02 41.0, 10m)", without the quotes. This tells the SIMBAD computer you are interested in a circular region of the celestial sphere centered on the coordinates for alpha Apodis, with a radius of 10 arcminutes (m).

Notice on the page over at the right from the tan colored box: "Return". The default is "object count". Click on "submit query". In a few moments a result something like "Number of objects:	   	 7" should appear. Click "Back" to see the tan box again.

Add "otype='X'" to the entry so that it reads: "region(14 47 51.73 -79 02 41.0, 10m) & otype='X'", without the outside quotes. Click on "submit query" again. If the result is "0" number of objects, increase the number of arcminutes, or use "1d" which stands for "one degree".

When you find at least one object, change "Return" to "display" by clicking on the circle to its left, then "submit query".

X-ray sources
There are several ways to evaluate an X-ray source for the constellation Apus.

Wikipedia source
Click on the link to the Wikipedia article on Alpha Apodis (α Aps). After you've enjoyed reading about the star, use the 'find' command of your browser to see if this Wikipedia page mentions anything about "X-ray", or "X-rays". Does the article mention whether or not Alpha Apodis is an X-ray source?

What is the current time stamp for the Wikipedia article on Alpha Apodis? [Hint]: look for something like "This page was last modified on 25 December 2011 at 20:12." very near the bottom of the page. For now this is an adequate time stamp.

From reading the Wikipedia article on Alpha Apodis, if you believe the text demonstrates that Alpha Apodis is not an X-ray source in Apus edit the "Non-X-ray source in Apus" section near the bottom of the page with an entry similar to "# Alpha Apodis 25 December 2011 at 20:12 Wikipedia article "Alpha Apodis".", without the outer quotes, and finish the entry with four "~"s without the quotes after the period. The date included with your designation or username is a time stamp for the entry. The last portion of the entry is the source of your information.

Is Wikipedia a 'primary source'?

Even though Wikipedia has an article on Alpha Apodis, is it a good place to stop in testing whether Alpha Apodis has been detected as an astronomical X-ray source?

SIMBAD source
Provided under 'External links' at the bottom of this page are a number of helpful links. If your browser allows you to view a second window in parallel with this one, click of the external link to the "SIMBAD Astronomical Database".

At the lower right side of the SIMBAD Astronomical Database page is a "Basic search" box. There are several ways to try your target:
 * 1) source name: without the quotes use "alpha Aps", "alpha apodis", or "Alpha Apodis" or
 * 2) source coordinates: without the quotes "14 47 51.73 -79 02 41.0".

If "alpha apodis" does not work, try "alpha Aps".

The names take you directly to "* alf Aps", but the coordinates yield a list, what's the difference between "* alf Aps" in the table and "Alpha Apodis" on Wikipedia?

If you are looking at the table which lists possible targets, click on the entry "* alf Aps" to look at the entry.

On the page "* alf Aps" read down the left side until you see "Other object types:". To the right of this is a list of other object types that Alpha Apodis is. Look for an X. Is there one in this horizontal list?

SIMBAD time stamp
Peruse the SIMBAD page for a time stamp or date of last revision. [Hint: it may look something like "2012.01.09CET20:10:02" and be in the upper right.]

If the entry at SIMBAD convinces you that Alpha Apodis is not an X-ray source, edit the "Non-X-ray source in Apus" section near the bottom of this page and type in an entry similar to "# Alpha Apodis 2012.01.09CET20:10:02 SIMBAD article "* alf Aps".", without the first set of quotes, followed by four ~s.

If your SIMBAD analysis convinces you that you have found an X-ray source in Apus (did you check the coordinates vs. the map of Apus?), make an entry something like the following in the section "X-ray source in Apus".

Challenging an entry
Is SIMBAD a 'primary source'?

SIMBAD is an astronomical database provided by the Centre de Données astronomiques de Strasbourg. It is an authoritative source, but they do occasionally make a mistake.

If you find an X-ray source within the constellation on SIMBAD, the next step is to find the earliest time stamp of discovery.

Wikipedia test source
Further down the SIMBAD page for "* alf Aps" is a list of "Identifiers (23)". Primary source literature may use any of these to include the star in their experimental observations. From the 'External links' near the bottom of this page, try a search with text something like "alpha apodis" "X-rays" or "X-ray".

For some sources, designations such as "HR 5470", "HD 129078", "SAO 257193", or "UBV 12790" may be more productive. If none of these works, try another star.

SIMBAD test source
Further down the SIMBAD page is a list of "Identifiers". Click on the blue bold portion.

On the page that appears should be a primary source listed after Ref:. Click on the blue link with the oldest year. This yields an earlier time stamp and entry citation like the current one in the section "X-ray source in Apus". If you find another source or an earlier time stamp, compose a similar entry and edit the section. Additional information to add into the reference can be found by clicking on "ADS services" from the SIMBAD page.

Changing an entry
From your analysis of Alpha Apodis so far, is it an X-ray source?

If you have found an earlier time stamp for alpha apodis than the one listed in the section below "Non-X-ray source in Apus" and the answer to the above question is "no", you can edit the section with your result. Or, you can leave the entries as is and try another star.

X-ray sources in Apus

 * 1) 1RXS J143729.3-791432 1999 SIMBAD article "1RXS J143729.3-791432" "the all-sky survey [was] performed during the first half year (1990/91) of the ROSAT mission." Marshallsumter (talk) 00:14, 27 February 2012 (UTC)
 * 2) Gamma Apodis (gam Aps on SIMBAD) X-ray source 1RXS J163329.7-785341, "the all-sky survey [was] performed during the first half year (1990/91) of the ROSAT mission." Marshallsumter (talk) 00:35, 27 February 2012 (UTC)
 * 3) 1RXS J143729.3-791432 2012.01.09CET21:26:56 SIMBAD article "1RXS J143729.3-791432". Marshallsumter 22:44, 9 January 2012 (UTC)

Non-X-ray sources in Apus

 * 1) Alpha Apodis 2012.01.09CET20:10:02 SIMBAD article "* alf Aps". Marshallsumter 20:02, 9 January 2012 (UTC)
 * 2) Alpha Apodis 25 December 2011 at 20:12 Wikipedia article "Alpha Apodis". Marshallsumter 20:02, 9 January 2012 (UTC)
 * 3) Gamma Apodis 29 December 2010 at 23:29 from the Wikipedia article. Marshallsumter (talk) 00:22, 27 February 2012 (UTC)
 * 4) bet Aps 2012.06.03CEST03:01:13 SIMBAD article "LTT 6652 -- High proper-motion Star". Marshallsumter (talk) 01:13, 3 June 2012 (UTC)
 * 5) Delta Apodis 14 March 2013 at 17:23 from the Wikipedia article. --Marshallsumter (discuss • contribs) 20:02, 21 April 2013 (UTC)
 * 6) Epsilon Apodis 14 April 2013 at 18:56 from the Wikipedia article. --Marshallsumter (discuss • contribs) 20:07, 21 April 2013 (UTC)
 * 7) Zeta Apodis 1 March 2013 at 02:52 from the Wikipedia article. --Marshallsumter (discuss • contribs) 20:07, 21 April 2013 (UTC)
 * 8) Eta Apodis 14 March 2013 at 17:24 from the Wikipedia article. --Marshallsumter (discuss • contribs) 20:10, 21 April 2013 (UTC)
 * 9) Theta Apodis 27 February 2013 at 09:00 from the Wikipedia article. --Marshallsumter (discuss • contribs) 20:13, 21 April 2013 (UTC)
 * 10) Iota Apodis 14 April 2013 at 19:46 from the Wikipedia article. --Marshallsumter (discuss • contribs) 20:13, 21 April 2013 (UTC)
 * 11) Kappa1 Apodis 19 March 2013 at 11:39 from the Wikipedia article. --Marshallsumter (discuss • contribs) 20:18, 21 April 2013 (UTC)
 * 12) Kappa2 Apodis 14 April 2013 at 19:49 from the Wikipedia article. --Marshallsumter (discuss • contribs) 20:18, 21 April 2013 (UTC)
 * 13) R Apodis 27 February 2013 at 12:02 from the Wikipedia article. --Marshallsumter (discuss • contribs) 20:54, 21 April 2013 (UTC)
 * 14) S Aps 2013.04.21CEST22:55:28 SIMBAD article "V* S Aps". --Marshallsumter (discuss • contribs) 20:58, 21 April 2013 (UTC)
 * 15) MY Aps 2013.04.21CEST22:58:52 SIMBAD article "V* MY Aps". --Marshallsumter (discuss • contribs) 21:01, 21 April 2013 (UTC)
 * 16) MN Aps 2013.04.21CEST23:01:47 SIMBAD article "V* MN Aps". --Marshallsumter (discuss • contribs) 21:07, 21 April 2013 (UTC)
 * 17) NO Aps 2013.04.21CEST23:08:29 SIMBAD article "V* NO Aps". --Marshallsumter (discuss • contribs) 21:11, 21 April 2013 (UTC)

Hypotheses

 * 1) The first X-ray source in Apus may be that portion of the Chamaeleon star-forming region that overlaps into Apus.


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University of Canberra/RCC2012/Potential topics

RCC is an unconference, where the sessions during the day are determined by the attendees each morning. This page allows attendees to record their ideas before the first day. There is no guarantee that these topics will be selected to be sessions at the unconference.

Wikisource
Try and stop me talking about Wikisource -- John Vandenberg

OTRS
There have been a few workshops on OTRS: WMDE and WMUK (OTRS workshop). It would be useful to start a discussion in Australia about this. The issues are broader than Wikimedia, including complaints about wiki content, privacy considerations, etc.


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User:Tomaschwutz/myskin.css

@import "http://www.wutzler.net/reh/index.php?title=User:tomaschwutz/myskin.css&action=raw&ctype=text/css"

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Government-Business Relations

Lecturer: Michael de Percy

Frequently asked questions: Click here for FAQs

PLEASE NOTE THAT THIS SITE IS NOT TO BE USED FOR 6606 GOVERNMENT-BUSINESS RELATIONS AT THE UNIVERSITY OF CANBERRA IN SEMESTER 1, 2012.Madepercy 02:10, 6 February 2012 (UTC)

The relationships which link government and business, the two primary institutions in society, are inherently complex. Analysing these relationships is an essential element in understanding how society is organised. This unit considers a number of Australian policy choices and major international issues from a government-business relations perspective, taking into account both domestic and international contexts. Such a combination of insights will provide a strong understanding of complex interactions between government and business at the local, national, and international levels.

Lecture Topics

 * Topic 1: Capitalism: Fundamental Concepts
 * Topic 2: Setting the Standard: Researching and Writing
 * Topic 3: Business, Government and Globalisation
 * Topic 4: Political Ideologies: Ideas and Institutions
 * Topic 5: Power & Policy: Pluralism, Elitism & Corporatism
 * Topic 6: Trade & Industry Policy: From Protectionism to Free Trade
 * Topic 7: Regulation: Monopoly, Public Goods & Externalities
 * Topic 8: Global Governance: Multinational Corporations & International Institutions
 * Topic 9: Political Science: The Comparative Method
 * Topic 10: 'Most Different' Comparison: Sweden, Germany & Japan
 * Topic 11: 'Most Similar' Comparison: Canada & Australia
 * Topic 12: Government, Business & Technology

Please click here to see details of tutorial activities

Assessment Items
This unit is assessed as follows:

To pass this unit, you MUST submit all assessment items AND obtain at least 40% in the final exam AND obtain a mark of at least 50% overall. Failure to submit any assessment item automatically results in a fail grade for the unit. Unless an official extension is granted, assessment items must be submitted no later than one week after the due date to be counted as “submitted”. Assessment items submitted later than one week after the due date will not be regarded as “submitted” and will not be marked.

Assignment 1: 20% Referencing & Researching Activity 500 words, due 5pm Friday Week 5 Assignment 2: 40% Academic Essay 2,000 words, due 9am Friday Week 12 Assignment 3: 40% Final Exam 80 multiple choice questions, 2 hours, Exam Period. Total:       100%

NOTE: To pass this unit, you MUST submit all assessment items AND obtain a minimum of 40% in the final exam AND obtain a mark of at least 50% overall. Failure to submit any assessment item automatically results in a fail grade for the unit. Unless an official extension is granted, assessment items must be submitted no later than one week after the due date to be counted as “submitted”. Assessment items submitted later than one week after the due date will not be regarded as “submitted” and therefore will not be marked.

Do not attend exams if you are ill - obtain a doctor’s certificate or counsellor’s letter and apply for a deferred exam (via Student Central) within 72 hours of the actual exam time.

Purpose of the Unit
This unit provides students with an awareness of the relationship between political, economic, social and policy aspects of interaction between government and business in Australia and a selection of other countries. It investigates the extent of government influence, how power is distributed throughout society, the impact of interest groups on policy, and how government and business are organised in a global context. Students will also be provided with a historical insight into, and a thorough understanding of, the interplay of economics and politics in international capitalism and the changing global environment.

The unit is designed to stimulate critical thinking and informed analysis, but there are no neat and easy answers to key themes and arguments. In many, if not most, cases there is no single 'right' answer, but students should be able to support their positions with reference to generally accepted facts, an understanding of the readings and sound reasoning.

Learning Outcomes
On completion of this unit, students should be able to:
 * Describe the relationship between government, business and society;
 * Contrast theoretical traditions about the economic role of government;
 * Identify the role played by government in managing the economy and in pursuing social goals;
 * Demonstrate a sound knowledge of the ways that business and government respond to the dynamics of globalisation; and
 * Relate political, social and economic changes to changes in the national and global environments.

Generic Skills
This unit focuses particularly on the generic skills and attributes in the areas of communication, analysis and enquiry, social responsibility and personal attributes. The generic skills and attributes which graduates of the University of Canberra are expected to develop as a result of their study are listed here: https://guard.canberra.edu.au/policy/download.php?file_id=2143.

Delivery Mode

 * Lectures to provide you with an overview of key concepts and issues;
 * Computer lab tutorials to provide you with researching and referencing skills and opportunities for real-time feedback on your work;
 * A referencing assignment designed to develop your researching and referencing skills;
 * An individual academic essay to assess your knowledge and ability to communicate and sustain an argument in writing; and
 * A final exam (held during the normal exam period) to assess your knowledge of the key concepts and issues taught in this unit.

title: Government-Business Relations


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User:OpenScientist/Open grant writing/Wissenswert 2011/oami config

Configuration for Open Access Media Importer bot
to be parsed by OAMI


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Semantic MediaWiki/Introduction

Overview
Currently this is only a collection of links with question that were recorded while tomaschwutz was looking at this topic in 2012. See also the Semantic MediaWiki category.

Big pictures

 * What is it all about?
 * What is it good for?
 * Why is agreeing on common editing syntax advantages?
 * Introduction

 * What are the benefits compared to using categories?

 * Skim through the theorethical background.
 * Ontologies and the Semantic Web

Making use of the semantic data

 * What is the factbox?
 * What is a semantic browser
 * Browsing interfaces
 * example site

 * What is a semantic query?
 * example
 * Task: Find all people from Germany and their cities and states
 * property names can be found on e.g. on a user factbox
 * Semantic search

Providing the semantic data

 * How do I edit the semantic data?
 * How to I specify the type of a property?
 * Properties and types
 * unfortunately does not work on wikiversity: Berlin Germany
 * edit the notes of user Carl Berlin on referata, and revert your changes using the history.

 * How can you automaticall convert units?
 * e.g. Property:Area
 * Custom units

 * What are Semantic templates good for?
 * e.g. California
 * background: m:Help:A quick guide to templates

 * See how easy and powerful Service links can be used.

Semantic Forms

 * See how you can use Semantic Forms to
 * design Categories, Properties, Templates, and Forms

 * How can you use #arraymap to define multiple properties?
 * Why to use a space (&#32;) when defining categories?
 * Why to use a space (&#32;) when defining categories?

 * What is the syntax of form fields?
 * How do you use autocompleting?
 * How can you use a Category for autocompletion?
 * |values from category=Area of focus
 * How can you allow multiple inputs (seperated by commata)
 * |list
 * How can force the user to input values?
 * |mandatory
 * How can you have multiple instance of one template?
 * How can the user select from a category tree?
 * mw:Extension:CategoryTree must be installed.
 * mw:Extension:CategoryTree must be installed.

 * How you can use Maps?

More on semantic queries

 * Here you look closer on Semantic search

 * Selecting pages
 * Why is it important to specify a < directly after the double collon?
 * How do you compare text alphabetically?
 * Howe do you use the + wildcard symbol?
 * Pages of which namespace are selected by Help:+ ?
 * Does born in::!Boston query return results of pages that do not have the bon in property?
 * How do you use OR and ||?
 * What does |France||User:John Doe mean?
 * How do you use and for subqueries?
 * What does located in.member of::European Union mean?

 * Displaying information
 * ? does not restict results compared to query descriptions
 * use the empty format # do suppress all formatting and linking in subqueries
 * What are #cm, #-n, #-u and #ISO used for?
 * What are [output formats] fromat=count, csv, template, ul used for?

 * Inline queries
 * explain the meaning of the following

 * use to show a single value
 * What is the meaning of the following parameters?
 * limit, sort, order, align, default,
 * |limit=0 |searchLabel=Click to browse

 * How do you use Concepts
 * to define overview pages
 * to define dynamic categroies that can be used in further queries

 * How can you Query linked properties?

Inferencing

 * deducing new knowledge from entered information
 * Subcategories and subproperties
 * Why is it important to describe the exact meaning of a category or a property very clearly?
 * :: returns subCategories, : not

Practicing

 * scratchpad.referata
 * server often not reachable
 * twutz/reh

title: Semantic MediaWiki/Introduction


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User:Marshallsumter/Deletion concerns

These are comments concerning the current Deletion policy proposal that is being discussed at Wikiversity talk:Deletion policy.

Criteria
As I understand Criteria numbers 2, 4, 6-8, 10-13, no problem.

1. No educational objectives or discussion in history. Let's say the work is educational and no one else has discussed it as yet. Does this mean speedy deletion? How short is "shortly"?

3. Wikimedia's Terms of Use is directed toward contributor's copyright. US copyright law section 107 specifically allows limited use of quoted sentences or "in your own word" cited sentences or anywhere in between with citation from copyrighted works of anyone as both free and fair use. Automatically deleting a contribution that any custodian interprets as "Copyright works which do not satisfy Wikimedia's Terms of Use" that have nothing to do with its Terms of Use here is wrong. Better phrasing is "Contributor's copyrighted works which do not satisfy ...", but if contributor owns the copyright and freely contributes portions of the work here agrees to terms of use. Whole copyrighted works by one contributed by another is a copyright violation. Quoted or cited portions in compliance with section 107 are in compliance with Terms of Use. In short, "Copyright works which do not satisfy Wikimedia's Terms of Use" makes no sense.

5. "Blanked pages by author or by user for pages in their user space may be taken as a speedy deletion request." Wrong! These pages may be blanked for review, whether the page says so or not. A speedy deletion request may remove a potentially valuable learning resource before review is completed.

9. "Reposted works that ignore this deletion policy, unless significantly rewritten in a manner that does not warrant deletion." This phrasing is highly subjective and potentially harmful to resources at Wikiversity. An educational resource put up for deletion or deleted out of ignorance by a consensus should be reposted. The phrase "in a manner that does not warrant deletion" suggests a litmus test on learning resources.

Discussion "[C]ontributions from multiple participants" - it has been my experience that many of the resources I have contributed to or created are often regarded as beyond the expertise of many who may wish to sincerely contribute, on the one hand, and others who are totally negative to the contribution on the other. Such polarity would result in deletion, because reason may not prevail. Example, "Proton-antiproton annihilation" contribution to Wikipedia met with polarized ignorance.

title: User:Marshallsumter/Deletion concerns


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Statistical Analysis/Unit 3 Navigation

This is the main navigation page for Unit 3 of the course Introduction to Statistical Analysis, developed using openly licensed materials from Saylor.org's Introduction to Statistics. Below you will find a full description of Unit 3 in general, as well as for each subunit. Follow the links within each subunit description to access particular topics, or proceed directly to the Unit 3 Content Page.

UNIT 3: RANDOM VARIABLES AND DISTRIBUTIONS
In the last unit, you learned how to calculate probabilities in the framework of sample spaces, outcomes, and events. In this unit, you will build on those ideas and learn about random variables. A random variable describes the outcomes of a statistical experiment. A statistical distribution describes the numbers of times each possible outcome occurs in a sample. The values of a random variable can vary with each repetition of an experiment. Intuitively, a random variable is an observable that takes on values with certain probabilities.

A random variable can be classified as being either discrete or continuous depending on the values it assumes. Suppose you count the number of people who go to a coffee shop between 4pm and 5pm and the amount of money that they spend in that hour. In this case, the number of people is an example of a discrete random variable and the amount of money they spend is an example of a continuous random variable. In this unit, you will study probability problems involving random distributions. You will also learn about both discrete and continuous random variables and their applications. Finally, you will study an important example of a continuous distribution, the normal distribution, which is a bell-shaped distribution used widely in almost all disciplines.

A note from the book: “The values of discrete and continuous random variables can be ambiguous. For example, if X is equal to the number of miles (to the nearest mile) you drive to work, then X is a discrete random variable. You count the miles. If X is the distance you drive to work, then you measure values of X and X is a continuous random variable. How the random variable is defined is very important.”

Time Advisory
Time Advisory: This unit will take you 18 hours to complete.
 * Subunit 3.1: 6 hours
 * Subunit 3.2: 6 hours
 * Subunit 3.3: 6 hours

Learning Outcomes
Upon completion of this this unit, you will be able to:
 * Recognize and understand discrete probability distribution functions.
 * Calculate and interpret expected values.
 * Recognize the binomial probability distribution and apply it appropriately.
 * Recognize the Poisson probability distribution and apply it appropriately.
 * Recognize the geometric probability distribution and apply it appropriately.
 * Recognize the hypergeometric probability distribution and apply it appropriately.
 * Classify discrete word problems by their distributions.
 * Recognize and understand continuous probability density functions in general.
 * Recognize the uniform probability distribution and apply it appropriately.
 * Recognize the exponential probability distribution and apply it appropriately.
 * Recognize the normal probability distribution and apply it appropriately.
 * Recognize the standard normal probability distribution and apply it appropriately.
 * Compare normal probabilities by converting to the standard normal distribution.

Subunits
Unit two consists of three main topics:

Discrete Random Variables and Discrete Probability Distributions
This topic will introduce you the major concepts fundamental to probability and the terminology associated with them.

 * 3.1.1: Probability Distribution Functions
 * 3.1.2: Expected Value and Standard Deviation
 * 3.1.3: Common Discrete Probability Distributions

Continuous Random Variables

 * 3.2.1: Continuous Probability Functions
 * 3.2.1: Uniform Distribution
 * 3.2.1: Exponential Distribution

Normal Distribution

 * 3.3.1: The Standard Normal Distribution
 * 3.3.1: Z-scores
 * 3.3.1: Areas to the Left and Right of x

About the Resources in This Course
This course project draws upon three main types of resources:

The first are readings and video lectures from Barbara Illowsky and Susan Dean’s Collaborative Statistics, which is available freely under a Creative Commons Attribution 2.0 Generic (CC BY 2.0) license from the following location: http://cnx.org/content/col10522/latest/

The second type of resources in this course are lectures from Kahn Academy. These lectures are available under a Creative Commons Attribution-NonCommercial-ShareAlike 3.0 Unported (CC BY-NC-SA 3.0) license. Kahn Academy has many lectures available from http://www.khanacademy.org/

Finally, the above resources have been woven together and organized into a format analogous to a traditional college-level course by professional consultants that work as experts within the subject area. This process was facilitated by The Saylor Foundation. Additionally, if you have worked through all of the material contained in this project, you may be interested in taking the final exam provided by Saylor.org or completing other courses available there that are not yet on Wikiversity.

title: Statistical Analysis/Unit 3 Navigation


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Statistical Analysis/Unit 3 Content

Unit 3
This content is adapted from the Introduction to Statistics MA121/ECON104 Course at Saylor.org.

Probability Distribution Functions

 * Readings: Barbara Illowsky and Susan Dean’s Collaborative Statistics: “Chapter 4: Discrete Random Variables”
 * "Section 1: Discrete Random Variables”
 * "Section 2: Probability Distribution Function (PDF) for a Discrete Random Variable”

Instructions: Please read each of the linked sections above in their entirety.

 * Lecture: Khan Academy’s Statistics
 * “Introduction to Random Variables”
 * “Probability Density Functions"

Instructions: Please view the linked lecture titled “Introduction to Random Variables” (12:04 minutes). This lecture will provide an introduction to random variables and probability distribution functions. Then, view the “Probability Density Functions” lecture (10:02 minutes) to learn about probability density functions for continuous random variables.

Terms of Use: Please respect the copyright and terms of use displayed on the webpages displayed above.

Expected Value and Standard Deviation

 * Readings: Barbara Illowsky and Susan Dean’s Collaborative Statistics: “Chapter 4: Discrete Random Variables” :*“Section 3: Mean or Expected Value and Standard Deviation”

Instructions: Please read the entire section in its entirety.

 * Lecture: Khan Academy’s Statistics
 * “Expected Value: E(X)”

Instructions: Please view the lecture in its entirety (approximately 15 minutes). In this lecture, you will learn about how to calculate expected value.

Terms of Use: Please respect the copyright and terms of use displayed on the webpage displayed above.

Common Discrete Probability Distributions

 * Readings: Barbara Illowsky and Susan Dean’s Collaborative Statistics: “Chapter 4: Discrete Random Variables”
 * “Section 4: Common Discrete Probability Distribution Functions”
 * “Section 5: Binomial”
 * “Section 6: Geometric (optional)”
 * “Section 7: Hypergeometric (optional)”
 * “Section 8: Poisson”

Instructions: Please read each of the linked sections above in their entirety.

 * Lecture: Barbara Illowsky and Susan Dean’s Collaborative Statistics: Video Lecture 4: Discrete Distributions.

Instructions: Please view the lecture to the right in its entirety.

 * Assignment: Barbara Illowsky and Susan Dean’s Collaborative Statistics: “Chapter 4: Discrete Random Variables”
 * “Practice 1: Discrete Distribution”
 * “Practice 2: Binomial Distribution”
 * “Practice 3: Poisson Distribution”
 * “Practice 4: Geometric Distribution”
 * “Practice 5: Hypergeometric Distribution”

Instructions: Click on the hyperlinks titled “Practice 1: Discrete Distribution,” “Practice 2: Binomial Distribution,” “Practice 3: Poisson Distribution,” “Practice 4: Geometric Distribution,” and “Practice 5: Hypergeometric Distribution” and solve all the problems in these sections. Next, click on the hyperlink titled “Homework” and solve problems 1, 3, 5, 7, 9, 11, 13, 15, 17, 19, 21, 23, 25, 29, 31. Please click on the “[ Show Solution ]” link below the problem to check your solution.

 * Lecture: Khan Academy’s Statistics
 * “Binomial Distribution 1”
 * “Binomial Distribution 2”
 * “Binomial Distribution 3”
 * “http://www.khanacademy.org/video/binomial-distribution-4?playlist=Statistics Binomial Distribution 4]”

Instructions: Please view all four lectures in their entirety (approximately 47 minutes total). In the first three lectures, you will learn about the binomial distribution. In the fourth lecture, you will learn to use excel to visualize the basketball binomial distribution presented in the third video.

 * Lecture: Khan Academy’s Statistics
 * “Expected Value of Binomial Distribution”

Instructions: Please view the lecture in its entirety (approximately 17 minutes). In this lecture, you will learn about the expected value of a binomial distributed random variable.

 * Lecture: Khan Academy’s Statistics
 * “Poisson Process 1”
 * “Poisson Process 2”

Instructions: Please view the both lectures in their entirety (approximately 24 minutes total). In these lectures, you will learn about the Poisson processes and the Poisson distribution as well as the derivation of the Poisson distribution.

Terms of Use: Please respect the copyright and terms of use displayed on the webpages above.

Continuous Probability Functions

 * Readings: Barbara Illowsky and Susan Dean’s Collaborative Statistics: “Chapter 5: Continuous Random Variables”
 * “Section 1: Continuous Random Variables”
 * “Section 2: Continuous Probability Functions”

Instructions: Please read each of the linked sections above in their entirety.

Terms of Use: Please respect the copyright and terms of use displayed on the webpages

Uniform Distribution

 * Readings: Barbara Illowsky and Susan Dean’s Collaborative Statistics: “Chapter 5: Continuous Random Variables”
 * “Section 3: The Uniform Distribution”

Instructions: Please read each section above in its entirety.

Terms of Use: Please respect the copyright and terms of use displayed on the webpages.

Exponential Distribution

 * Readings: Barbara Illowsky and Susan Dean’s Collaborative Statistics: “Chapter 5: Continuous Random Variables”
 * “Section 4: The Exponential Distribution”

Instructions: Please read each section above in its entirety.

 * Lecture: Barbara Illowsky and Susan Dean’s Collaborative Statistics: “Video Lecture 5: Continuous Random Variables”

Instructions: Please view the lecture to the right.

 * Assignment: Barbara Illowsky and Susan Dean’s Collaborative Statistics: “Chapter 5: Continuous Random Variables”
 * “Practice 1: Uniform Distribution”
 * “Practice 2: Exponential Distribution”

Instructions: Click on the hyperlinks titled “Practice 1: Uniform Distribution,” “Practice 2: Exponential Distribution.”  Please solve all the problems in these two sections. Next, click on the hyperlink titled “Homework” and solve problems 3, 5, 7, 9, 11, 13, 15-20. The solutions are provided below the problem. Please solve all of the problems before checking the solutions.

Terms of Use: Please respect the copyright and terms of use displayed on the webpages.

The Standard Normal Distribution

 * Readings: Barbara Illowsky and Susan Dean’s Collaborative Statistics: “Chapter 6: The Normal Distribution"
 * "Section 1: The Normal Distribution”
 * “Section 2: The Standard Normal Distribution”

Instructions: Please read each of the linked sections above in their entirety.

 * Lecture: Khan Academy’s Statistics
 * “Law of Large Numbers”

Instructions: Please view the lecture in its entirety (9:00 minutes). In this lecture, you will learn about the law of large numbers.

 * Lecture: Khan Academy’s Statistics
 * “Normal Distribution Excel Exercise”
 * “Introduction to Normal Distribution”
 * “Normal Distribution Problems: Qualitative Sense of Normal Distributions”

Instructions: Please view the lectures linked above. In the lecture titled “Normal Distribution Excel Exercise” (26 minutes), you will see a presentation on a spreadsheet, which will show that the normal distribution approximates the binomial distribution for a large number of trials. Please view the other two lectures on normal distribution in their entirety (approximately 37 minutes total).

Z-scores

 * Readings: Barbara Illowsky and Susan Dean’s Collaborative Statistics: “Chapter 6: The Normal Distribution"
 * Section 3: Z-scores”

Instructions: Please read each section above in its entirety.

 * Lecture: Khan Academy’s Statistics
 * “Normal Distribution Problems: z-score”
 * “Normal Distribution Problems: Empirical Rule”
 * “Standard Normal Distribution and the Empirical Rule”

Instructions: Please view the three lectures in their entirety (approximately 26 minutes total). In these lecture, you will learn about the z-scores and how to use the empirical rule (the 68-95-99.7 rule) to estimate probabilities for normal distributions.

Terms of Use: Please respect the copyright and terms of use displayed on the webpages.

Areas to the Left and Right of x

 * Readings: Barbara Illowsky and Susan Dean’s Collaborative Statistics: “Chapter 6: The Normal Distribution"
 * "Section 4: Areas to the Left and Right of x”

Instructions: Please read each section above in its entirety.

Terms of Use: Please respect the copyright and terms of use displayed on the webpages.

Calculations of Probabilities

 * Readings: Barbara Illowsky and Susan Dean’s Collaborative Statistics: “Chapter 6: The Normal Distribution"
 * Section 5: Calculations of Probabilities”

Instructions: Please read each section above in its entirety.

 * Lecture: Barbara Illowsky and Susan Dean’s Collaborative Statistics: “Video Lecture 6: The Normal Distribution”

Instructions: Please view the lecture to the right in its entirety.

 * Assignment: Barbara Illowsky and Susan Dean’s Collaborative Statistics: “Chapter 6: The Normal Distribution”
 * “Practice: The Normal Distribution”

Instructions: Click on the hyperlink titled “Practice: The Normal Distribution”. Please solve all the problems in this section. Next, click on the hyperlink titled “Homework” and solve problems 1, 3, 5, 7, 9, 11, 12-19. The solutions are provided below the problem. Please solve all of the problems before checking the solutions.

Terms of Use: Please respect the copyright and terms of use displayed on the webpages.

About the Resources in This Course
This course project draws upon three main types of resources:

The first are readings and video lectures from Barbara Illowsky and Susan Dean’s Collaborative Statistics, which is available freely under a Creative Commons Attribution 2.0 Generic (CC BY 2.0) license from the following location: http://cnx.org/content/col10522/latest/

The second type of resources in this course are lectures from Kahn Academy. These lectures are available under a Creative Commons Attribution-NonCommercial-ShareAlike 3.0 Unported (CC BY-NC-SA 3.0) license. Kahn Academy has many lectures available from http://www.khanacademy.org/

Finally, the above resources have been woven together and organized into a format analogous to a traditional college-level course by professional consultants that work as experts within the subject area. This process was facilitated by The Saylor Foundation. Additionally, if you have worked through all of the material contained in this project, you may be interested in taking the final exam provided by Saylor.org or completing other courses available there that are not yet on Wikiversity.

title: Statistical Analysis/Unit 3 Content