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e. The Oxford–AstraZeneca COVID‑19 vaccine, sold under the brand names Covishield [31] and Vaxzevria [1] [32] among others, is a viral vector vaccine for the prevention of COVID-19. It was developed in the United Kingdom by Oxford University and British-Swedish company AstraZeneca, [33] [34] [35] using as a vector the modified chimpanzee ...
D05295. The smallpox vaccine is the first vaccine to have been developed against a contagious disease. In 1796, British physician Edward Jenner demonstrated that an infection with the relatively mild cowpox virus conferred immunity against the deadly smallpox virus. Cowpox served as a natural vaccine until the modern smallpox vaccine emerged in ...
Human papillomavirus infection ( HPV infection) is caused by a DNA virus from the Papillomaviridae family. [5] Many HPV infections cause no symptoms and 90% resolve spontaneously within two years. [1] In some cases, an HPV infection persists and results in either warts or precancerous lesions. [2] These lesions, depending on the site affected ...
- 新冠肺炎-疫苗資訊最前線
- Conventional Order
- Special Cases
- Mnemonics
- Calculators
- Programming Languages
- See Also
- Further Reading
- External Links
The order of operations, that is, the order in which the operations in an expression are usually performed, results from a convention adopted throughout mathematics, science, technology and many computer programming languages. It is summarized as: 1. Parentheses 2. Exponentiation 3. Multiplication and division 4. Addition and subtraction This means...
Unary minus sign
There are differing conventions concerning the unary operation '−' (usually pronounced "minus"). In written or printed mathematics, the expression −32 is interpreted to mean −(32) = −9. In some applications and programming languages, notably Microsoft Excel, PlanMaker (and other spreadsheet applications) and the programming language bc, unary operations have a higher priority than binary operations, that is, the unary minus has higher precedence than exponentiation, so in those languages −32...
Mixed division and multiplication
There is no universal convention for interpreting a term containing both division denoted by '÷' and multiplication denoted by '×'. Proposed conventions include assigning the operations equal precedence and evaluating them from left to right, or equivalently treating division as multiplication by the reciprocal and then evaluating in any order;evaluating all multiplications first followed by divisions from left to right; or eschewing such expressions and instead always disambiguating them by...
Serial exponentiation
If exponentiationis indicated by stacked symbols using superscript notation, the usual rule is to work from the top down: 1. abc = a(bc) which typically is not equal to (ab)c. This convention is useful because there is a property of exponentiation that (ab)c = abc, so it's unnecessary to use serial exponentiation for this. However, when exponentiation is represented by an explicit symbol such as a caret (^) or arrow (there is no common standard. For example, Microsoft Excel and computatio...
Mnemonicsare often used to help students remember the rules, involving the first letters of words representing various operations. 1. The acronym PEMDAS is common in the United States and France. It stands for Parentheses, Exponents, Multiplication/Division, Addition/Subtraction.PEMDAS is sometimes expanded to the mnemonic "Please Excuse My Dear Au...
Different calculators follow different orders of operations. Many simple calculators without a stack implement chain input, working in button-press order without any priority given to different operations, give a different result from that given by more sophisticated calculators. For example, on a simple calculator, typing 1 + 2 × 3 = yields 9, whi...
Most programming languages use precedence levels that conform to the order commonly used in mathematics, though others, such as APL, Smalltalk, Occam and Mary, have no operatorprecedence rules (in APL, evaluation is strictly right to left; in Smalltalk, it is strictly left to right). Furthermore, because many operators are not associative, the orde...
Fothe, Michael; Wilke, Thomas, eds. (2015). Keller, Stack und automatisches Gedächtnis – eine Struktur mit Potenzial [Cellar, stack and automatic memory – a structure with potential] (PDF). Kolloqu...
Bergman, George Mark (2013). "Order of arithmetic operations; in particular, the 48/2(9+3) question". Dept. of Mathematics, University of California. Retrieved 2020-07-22.Zachary, Joseph L. (1997) "Operator Precedence", supplement to Introduction to Scientific Programming. University of Utah. Maple worksheet, Mathematica notebook.Hasse diagram of the preorder x R y defined by x//4≤y//4 on the natural numbers.Equivalence classes (sets of elements such that x R y and y R x) are shown together as a single node.The relation on equivalence classes is a partial order. In mathematics, especially in order theory, a preorder or quasiorder is a binary relation that is reflexive and transitive.
Doctor Who. episodes (2005–present) Doctor Who is a British science fiction television programme produced by the BBC. As of 1 June 2024, 880 episodes of Doctor Who have aired. This includes one television movie and multiple specials, and encompasses 309 stories over 40 seasons, starting in 1963. Additionally, four charity specials and two ...
1 Control-C has typically been used as a "break" or "interrupt" key. 2 Control-D has been used to signal "end of file" for text typed in at the terminal on Unix / Linux systems. Windows, DOS, and older minicomputers used Control-Z for this purpose. 3 Control-G is an artifact of the days when teletypes were in use.
