Opal Cone

Opal Cone is a cinder cone located on the southeast flank of Mount Garibaldi in the Coast Mountains of British Columbia, Canada. It is the source of a 15 km long broad dacite lava flow with prominent wrinkled ridges. The lava flow is unusually long for a silicic lava flow.

Opal Cone is a member of the Cascade Volcanoes, but it is located in the Garibaldi Ranges in the Coast Mountains and not in the Cascade Range proper.

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List of recurring The Simpsons characters

The Simpsons includes a large array of supporting characters: co-workers, teachers, family friends, extended relatives, townspeople, local celebrities, fictional characters within the show, and even animals. The writers originally intended many of these characters as one-time jokes or for fulfilling needed functions in the town. A number of them have gained expanded roles and have subsequently starred in their own episodes. According to the creator of The Simpsons, Matt Groening, the show adopted the concept of a large supporting cast from the Canadian sketch comedy show Second City Television.

Agnes Skinner

Agnes Skinner (voiced by Tress MacNeille) is the mother of Principal Skinner and first appeared in the first season episode "The Crepes of Wrath" as an old woman who embarrassingly calls her son "Spanky". However, as episodes progressed, the character turned bitter. She is very controlling of her son and often treats him as if he is a child. She hates Edna Krabappel due to her son's feelings for the other woman. Agnes has married four times. Several Springfield residents (including the Simpsons) are afraid of her. When "the real Seymour Skinner" arrives in Springfield, Agnes ends up rejecting him in part because he stands up to her, but also because unlike Skinner/Tamzarian, her biological son is independent and doesn't need her anymore, while Skinner immediately reverts to a good-for-nothing without her.

Large Electron–Positron Collider

The Large Electron–Positron Collider (LEP) was one of the largest particle accelerators ever constructed.

It was built at CERN, a multi-national centre for research in nuclear and particle physics near Geneva, Switzerland. LEP collided electrons with positrons at energies that reached 209 GeV. It was a circular collider with a circumference of 27 kilometres built in a tunnel roughly 100 m (300 ft) underground and passing through Switzerland and France. LEP was used from 1989 until 2000. Around 2001 it was dismantled to make way for the LHC, which re-used the LEP tunnel. To date, LEP is the most powerful accelerator of leptons ever built.

Collider Background

LEP was a circular lepton collider – the most powerful such ever built. For context, modern colliders can be generally categorized based on their shape (circular or linear) and on what types of particles they accelerate and collide (leptons or hadrons). Leptons are point particles and are relatively light. Because they are point particles, their collisions are clean and amenable to precise measurements; however, because they are light, the collisions cannot reach the same energy that can be achieved with heavier particles. Hadrons are composite particles (composed of quarks) and are relatively heavy; protons, for example, have a mass 2000 times greater than electrons. Because of their higher mass, they can be accelerated to much higher energies, which is the key to directly observing new particles or interactions that are not predicted by currently accepted theories. However, hadron collisions are very messy (there are often lots of unrelated tracks, for example, and it is not straightforward to determine the energy of the collisions), and therefore more challenging to analyze and less amenable to precision measurements.

Opal (disambiguation)

An opal is a gemstone.

Opal may also refer to:

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Other sciences

Conical hill

A conical hill (also cone or conical mountain) is a landform with a distinctly conical shape. It is usually isolated or rises above other surrounding foothills, and is often, but not always, of volcanic origin.

Conical hills or mountains occur in different shapes and are not necessarily geometrically-shaped cones; some are more tower-shaped or have an asymmetric curve on one side. Typically, however, they have a circular base and smooth sides with a gradient of up to 30°. Such conical mountains are found in all volcanically-formed areas of the world such as the Bohemian Central Uplands in the Czech Republic, the Rhön in Germany or the Massif Central in France.

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Cone cell

Cone cells, or cones, are one of two types of photoreceptor cells in the retina of the eye. They are responsible for color vision and function best in relatively bright light, as opposed to rod cells, which work better in dim light. Cone cells are densely packed in the fovea centralis, a 0.3 mm diameter rod-free area with very thin, densely packed cones which quickly reduce in number towards the periphery of the retina. There are about six to seven million cones in a human eye and are most concentrated towards the macula.

A commonly cited figure of six million in the human eye was found by Osterberg in 1935. Oyster's textbook (1999) cites work by Curcio et al. (1990) indicating an average close to 4.5 million cone cells and 90 million rod cells in the human retina.

Cones are less sensitive to light than the rod cells in the retina (which support vision at low light levels), but allow the perception of colour. They are also able to perceive finer detail and more rapid changes in images, because their response times to stimuli are faster than those of rods. Cones are normally one of the three types, each with different pigment, namely: S-cones, M-cones and L-cones. Each cone is therefore sensitive to visible wavelengths of light that correspond to short-wavelength, medium-wavelength and long-wavelength light. Because humans usually have three kinds of cones with different photopsins, which have different response curves and thus respond to variation in colour in different ways, we have trichromatic vision. Being colour blind can change this, and there have been some verified reports of people with four or more types of cones, giving them tetrachromatic vision. The three pigments responsible for detecting light have been shown to vary in their exact chemical composition due to genetic mutation; different individuals will have cones with different color sensitivity. Destruction of the cone cells from disease would result in blindness.

Cone (linear algebra)

In linear algebra, a (linear) cone is a subset of a vector space that is closed under multiplication by positive scalars. In other words, a subset C of a real vector space V is a cone if and only if λx belongs to C for any x in C and any positive scalar λ of V (or, more succinctly, if and only if λC = C for any positive scalar λ).

A cone is said to be pointed if it includes the null vector (origin) 0; otherwise it is said to be blunt. Some authors use "non-negative" instead of "positive" in this definition of "cone", which restricts the term to the pointed cones only. In other contexts, a cone is pointed if the only linear subspace contained in it is {0}.

The definition makes sense for any vector space V which allows the notion of "positive scalar" (i.e., where the ground field is an ordered field), such as spaces over the rational, real algebraic, or (most commonly) real numbers.

The concept can also be extended for any vector space V whose scalar field is a superset of those fields (such as the complex numbers, quaternions, etc.), to the extent that such a space can be viewed as a real vector space of higher dimension.