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6 天前 · Principal component analysis ( PCA) is a linear dimensionality reduction technique with applications in exploratory data analysis, visualization and data preprocessing . The data is linearly transformed onto a new coordinate system such that the directions (principal components) capturing the largest variation in the data can be easily identified.
2024年5月1日 · The resistivity can be expressed using the SI unit ohm metre (Ω⋅m) — i.e. ohms multiplied by square metres (for the cross-sectional area) then divided by metres (for the length).Both resistance and resistivity describe how difficult it is to make electrical current flow through a material, but unlike resistance, resistivity is an intrinsic property and does not depend on geometric ...
- ρ
- ohm metre (Ω⋅m)
- kg⋅m³⋅s−3⋅A−2
2 天前 · C. S. Lewis. For the Anglo-Irish poet, see Cecil Day-Lewis. Clive Staples Lewis FBA (29 November 1898 – 22 November 1963) was a British writer, literary scholar, and Anglican lay theologian. He held academic positions in English literature at both Magdalen College, Oxford (1925–1954), and Magdalene College, Cambridge (1954–1963).
4 天前 · Down syndrome or Down's syndrome, also known as trisomy 21, is a genetic disorder caused by the presence of all or part of a third copy of chromosome 21. [3] It is usually associated with developmental delays, mild to moderate intellectual disability, and characteristic physical features. [1] [12] There are three types of Down syndrome, the ...
- Third copy of chromosome 21
- Mostly at conception, rarely after fertilization
20 小時前 · The 2024 NFL draft was the 89th annual meeting of National Football League (NFL) franchises to select newly eligible players. The draft was held at Campus Martius Park and Hart Plaza in Detroit, Michigan on April 25–27, 2024.[1] The draft had a peak attendance of 275,000, breaking the record set previously in 2019.[2] A record six ...
1 天前 · James Earl Carter Jr. (born October 1, 1924) is an American politician and humanitarian who served as the 39th president of the United States from 1977 to 1981. A member of the Democratic Party, Carter was the 76th governor of Georgia from 1971 to 1975, and a Georgia state senator from 1963 to 1967. At age 99, he is both the oldest living ...
1 天前 · cia .gov. The Central Intelligence Agency ( CIA / ˌsiː.aɪˈeɪ /; known informally as the Agency [6] and historically as the Company) [7] is a civilian foreign intelligence service of the federal government of the United States, officially tasked with gathering, processing, and analyzing national security information from around the world ...
