Del

Del, or nabla, is an operator used in mathematics, in particular, in vector calculus, as a vector differential operator, usually represented by the nabla symbol ∇. When applied to a function defined on a one-dimensional domain, it denotes its standard derivative as defined in calculus. When applied to a field (a function defined on a multi-dimensional domain), del may denote the gradient (locally steepest slope) of a scalar field (or sometimes of a vector field, as in the Navier–Stokes equations), the divergence of a vector field, or the curl (rotation) of a vector field, depending on the way it is applied.

Strictly speaking, del is not a specific operator, but rather a convenient mathematical notation for those three operators, that makes many equations easier to write and remember. The del symbol can be interpreted as a vector of partial derivative operators, and its three possible meanings—gradient, divergence, and curl—can be formally viewed as the product with a scalar, dot product, and cross product, respectively, of the del "operator" with the field. These formal products do not necessarily commute with other operators or products.

Deel (clothing)

A deel (Mongolian: дээл [teːɮ]; Buryat: дэгэл) is an item of traditional clothing commonly worn since centuries ago among the Mongols and other nomadic tribes of Central Asia, including various Turkic peoples, and can be made from cotton, silk, wool, or brocade. The deel is still commonly worn by both men and women outside major towns, especially by herders. In urban areas, deels are mostly only worn by elderly people, or on festive occasions. The deel appears similar to a caftan or an old European folded tunic. Deels typically reach to below the wearer's knees and fan out at the bottom and are commonly blue, olive, or burgundy, though there are deels in a variety of other colors.

Description

The deel looks like a large overcoat when not worn. Instead of buttoning together in the middle, the sides are pulled against the wearers body, the right flap close to the body with the left covering. On the right side of the wearer are typically 5 or 6 clasps to hold the top flap in place. There is one clasp below the armpit, three at the shoulder, and either one or two at the neckline.

Alpha Delphini

Alpha Delphini (α Del, α Delphini) is a multiple star in the constellation Delphinus. It also has the name Sualocin, which was given to it as a practical joke by the astronomer Niccolò Cacciatore; the name is the Latinized version (Nicolaus) of his given name, spelled backwards.

In Chinese, 瓠瓜 (Hù Guā), meaning Good Gourd, refers to an asterism consisting of α Delphini, γ² Delphini, δ Delphini, β Delphini and ζ Delphini. Consequently, α Delphini itself is known as 瓠瓜一 (Hù Guā yī, English: the First Star of Good Gourd.).

Properties

Alpha Delphini has seven components: A and G, a physical binary, and B, C, D, E, and F, which are optical binaries and have no physical association with A and G.

See also

References

References

Pica

Pica or PICA may refer to:

Biology

Moths

Sea snails

Organizations

Pica (typography)

The pica is a typographic unit of measure corresponding to ¹⁄₇₂ of a foot, or ¹⁄₆ of an inch. The pica contains 12 point units of measure.

The pica originated around 1785, when François-Ambroise "L'éclat" Didot (1730–1804) refined the typographic measures system created by Pierre Simon Fournier le Jeune (1712–1768). He replaced the traditional measures of cicéro, Petit-Roman, and Gros-Text with "ten-point", "twelve-point", etc.

To date, in printing these three pica measures are used:

Note that these definitions are different from a typewriter's pica setting, which denotes a type size of ten characters per horizontal inch.

Usually, pica measurements are represented with an upper-case "P" with an upper-right-to-lower-left virgule (slash) starting in the upper right portion of the "P" and ending at the lower left of the upright portion of the "P"; essentially drawing a virgule ( / ) through a "P". (P̸) Likewise, points are represented with number of points before a lower-case "p", for example, 5p represents "5 points", and 6P̸2p represents "6 picas and 2 points", and 1P̸1 represents "13 points", which is converted to a mixed fraction of 1 pica and 1 point.

Pica (genus)

Pica is the genus of two to four species of birds in the family Corvidae in both the New World and the Old. They have long tails and have predominantly black and white markings. One species ranges widely from Europe through Asia, one occurs in western North America and the third is restricted to California. They are usually considered closely related to the blue and green magpies of Asia, but recent research suggests their closest relatives are instead the Eurasian crows.

Two or three species were generally recognized, the Yellow-billed and one or two black-billed ones. Recent research has cast doubt on the taxonomy of the Pica magpies.P. hudsonia and P. nuttalli are each other's closest relatives, but may not be different species. If they are, however, at least the Korean race of P. pica would have to be considered a separate species, too.