Sprint (running)

Sprinting is the act of running over a short distance at (or near) top speed. It is used in many sports that incorporate running, typically as a way of quickly reaching a target or goal, or avoiding or catching an opponent. Human physiology dictates that a runner's near-top speed cannot be maintained for more than 30–35 seconds due to the depletion of Phosphocreatine stores in muscles, and perhaps secondarily to excessive Metabolic acidosis as a result of Anaerobic glycolysis.

In athletics and track and field, sprints (or dashes) are races over short distances. They are among the oldest running competitions. The first 13 editions of the Ancient Olympic Games featured only one event—the stadion race, which was a race from one end of the stadium to the other. There are three sprinting events which are currently held at the Summer Olympics and outdoor World Championships: the 100 metres, 200 metres, and 400 metres. These events have their roots in races of imperial measurements which were later altered to metric: the 100 m evolved from the 100 yard dash, the 200 m distances came from the furlong (or 1/8 of a mile), and the 400 m was the successor to the 440 yard dash or quarter-mile race.

500 kHz

Since early in the 20th century, the radio frequency of 500 kilohertz (500 kHz) has been an international calling and distress frequency for Morse code maritime communication. The unit kilohertz was not introduced until the 1960s. For most of its history, the international distress frequency was referred to by its equivalent wavelength, 600 meters, or, using the earlier frequency unit name, 500 kilocycles (per second) or 500 kc.

The United States Coast Guard and comparable agencies of other nations used to maintain 24-hour watches on this frequency, staffed by highly skilled radio operators. Many SOS calls and medical emergencies at sea were handled here until the late 1980s. However, because of the near disappearance of the commercial use of Morse code, the frequency is now rarely used. Emergency traffic on 500 kHz has been almost completely replaced by the Global Maritime Distress Safety System (GMDSS). Beginning in the late 1990s, most nations ended monitoring of transmissions on 500 kHz. The nearby frequencies of 518 kHz and 490 kHz are used for the Navtex component of GMDSS. Proposals to allocate frequencies at or near 500 kHz to amateur radio use resulted in the creation of the 600-meter amateur radio band.

White Rock

White Rock or White Rocks may refer to:

Places

Australia

Canada

United States

Shanghai Tower

The Shanghai Tower (Chinese: 上海中心大厦; pinyin: Shànghǎi Zhōngxīn Dàshà; literally: "Shanghai Center Tower") is a megatall skyscraper in Lujiazui, Pudong, Shanghai. Designed by Gensler and owned by a consortium of Chinese state-owned companies, it is the tallest of a group of three adjacent supertall buildings in Pudong, the other two being the Jin Mao Tower and the Shanghai World Financial Center. The building is 632 metres (2,073 ft) high and has 128 stories, with a total floor area of 380,000 m² (4,090,000 sq ft). Its tiered construction, designed for high energy efficiency, provides multiple separate zones for office, retail and leisure use. The Shanghai Tower was completed in the summer of 2015.

Construction work on the tower began in November 2008. Following its topping out on 3 August 2013, the Shanghai Tower is currently the tallest building in China and the second-tallest in the world, surpassed only by the Burj Khalifa in Dubai. It was scheduled to open to the public in June 2015, but this has not happened as of late November 2015. It is also China's tallest structure of any kind, surpassing the 600-metre (1,969 ft) Canton Tower in Guangzhou completed in 2010.