Xi Jiang

 

(shē) or Xi Jiang (shē jyäng) , great river of S China, c.1,250 mi (2,010 km) long, rising in E Yunnan prov. and flowing generally E through Guangxi and Guangdong provs. to the South China Sea near Guangzhou; the Kui, Bei, and Dong rivers are its chief tributaries. The Xi flows mainly through narrow, confined valleys. At the junction with the Bei, W of Guangzhou, the Xi forms the vast Pearl River delta (2,890 sq mi/7,485 sq km), consisting of a maze of channels and canals. The densely populated delta is one of China's chief economic areas; agriculture (rice, sugarcane, fruit) predominates. One of China's principal inland waterways, the Xi is navigable for large ships along almost half of its length. It is also called the West River.

Greek alphabet
Αα Alpha	Νν Nu
Ββ Beta	Ξξ Xi
Γγ Gamma	Οο Omicron
Δδ Delta	Ππ Pi
Εε Epsilon	Ρρ Rho
Ζζ Zeta	Σσ Sigma
Ηη Eta	Ττ Tau
Θθ Theta	Υυ Upsilon
Ιι Iota	Φφ Phi
Κκ Kappa	Χχ Chi
Λλ Lambda	Ψψ Psi
Μμ Mu	Ωω Omega
Obsolete letters
Ϝϝ Digamma	Ϙϙ Qoppa
Ϛϛ Stigma	Ϡϡ Sampi
Ϻϻ San	Ϸϸ Sho
Greek diacritics

Xi (uppercase Ξ, lowercase ξ) is the 14th letter of the Greek alphabet. It is pronounced [zaɪ] by US English speakers, but [ksi] is the correct Greek pronunciation. The Greek pronunciation has also become fairly common among mathematicians, even speaking in English. In the system of Greek numerals, it has a value of 60. Its Latin equivalent is X.

The lower-case letter ξ is used as a symbol for

• random variables;
• extent of reaction (a topic found most often in chemical engineering kinetics);
• eigenvectors;
• a parameter in a generalized Pareto distribution;
• the symmetric function equation of the Riemann zeta function in mathematics, also known as the Riemann Xi function;
• the damping factor in an RLC circuit;
• a universal set in the set theory;
• one of the two different polypeptide chains of the human embryonic hemoglobin types Hb-Portland (ξ₂γ₂) and Hb-Gower I (ξ₂ε₂).

The upper-case letter Ξ is used as symbol for

• The 'cascade particles' in particle physics;
• indicating "no change of state" in Z notation.

Xi was also adopted into the early Cyrillic alphabet, as the letter ksi (Ѯ, ѯ).

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