In vector calculus, the gradient of a scalar-valued differentiable function f of several variables is the vector field whose value at a point is the vector whose components are the partial derivatives of at . That is, for , its gradient is defined at the point in n-dimensional space as the vector:
Radon is a chemical element with the symbol Rn and atomic number 86. It is a radioactive, colorless, odorless, tasteless noble gas. It occurs naturally in minute quantities as an intermediate step in the normal radioactive decay chains through which thorium and uranium slowly decay into lead and various other short-lived radioactive elements. Radon itself is the immediate decay product of radium. Its most stable isotope, 222Rn, has a half-life of only 3.8 days, making it one of the rarest elements. Since thorium and uranium are two of the most common radioactive elements on Earth, while also having three isotopes with half-lives on the order of several billion years, radon will be present on Earth long into the future despite its short half-life. The decay of radon produces many other short-lived nuclides, known as radon daughters, ending at stable isotopes of lead.
Transport in Bolivia is mostly by road. The railways were historically important in Bolivia, but now play a relatively small part in the country's transport system. Because of the country's geography, aviation is also important.
Raymond Ames Spruance was a United States Navy admiral during World War II. He commanded U.S. naval forces during one of the most significant naval battles that took place in the Pacific Theatre: the Battle of the Philippine Sea. He also commanded Task Force 16 at the Battle of Midway, comprising the carriers Enterprise and Hornet. At Midway, dive bombers from the Enterprise crippled two carriers of the Imperial Japanese Navy, Kaga and the flagship Akagi. Most historians consider Midway the turning point of the Pacific War.
Jane's Fighting Ships is an annual reference book of information on all the world's warships arranged by nation, including information on ships' names, dimensions, armaments, silhouettes and photographs, etc. Each edition describes and illustrates warships of different national naval and paramilitary forces, providing data on their characteristics. The first issue was illustrated with Jane's own ink sketches--photos began to appear with the third volume in 1900. The present title was adopted in 1905.
The Honda K-series engine is a line of four-cylinder four-stroke car engine introduced in 2001. The K-series engines are equipped with DOHC valvetrains and use roller rockers to reduce friction. The engines use a coil-on-plug, distributorless ignition system with a coil for each spark plug. This system forgoes the use of a conventional distributor-based ignition timing system in favor of a computer-controlled system that allows the ECU to control ignition timings based on various sensor inputs. The cylinders have cast iron sleeves similar to the B- and F-series engines, as opposed to the FRM cylinders found in the H- and newer F-series engines found only in the Honda S2000.
This page shows the electron configurations of the neutral gaseous atoms in their ground states. For each atom the subshells are given first in concise form, then with all subshells written out, followed by the number of electrons per shell. Electron configurations of elements beyond hassium are predicted. As an approximate rule, electron configurations are given by the Aufbau principle and the Madelung rule. However there are numerous exceptions; for example the lightest exception is chromium, which would be predicted to have the configuration 1s2 2s2 2p6 3s2 3p6 3d4 4s2, written as [Ar] 3d4 4s2, but whose actual configuration given in the table below is [Ar] 3d5 4s1.
A speaking tube or voicepipe is a device based on two cones connected by an air pipe through which speech can be transmitted over an extended distance.
Sir Raymond William Firth was an ethnologist from New Zealand. As a result of Firth's ethnographic work, actual behaviour of societies is separated from the idealized rules of behaviour within the particular society. He was a long serving Professor of Anthropology at London School of Economics, and is considered to have singlehandedly created a form of British economic anthropology.
North Secretary Island is located in the Gulf Islands where Trincomali Channel and Houstoun Passage meet in the Gulf Islands region of the South Coast of British Columbia, Canada. It is 138 acres (0.56 km2) in size and is located in Trincomali Channel as part of the Secretary Islands group off the north tip of Saltspring Island. There are two islands in the Secretary Islands group, the southern being named South Secretary and the larger one being named North Secretary Island. There is another Secretary Island in British Columbia, in Sooke Basin.
Tacit programming, also called point-free style, is a programming paradigm in which function definitions do not identify the arguments on which they operate. Instead the definitions merely compose other functions, among which are combinators that manipulate the arguments. Tacit programming is of theoretical interest, because the strict use of composition results in programs that are well adapted for equational reasoning. It is also the natural style of certain programming languages, including APL and its derivatives, and concatenative languages such as Forth. The lack of argument naming gives point-free style a reputation of being unnecessarily obscure, hence the epithet "pointless style".
HMS Ulster was a U-class destroyer of the Royal Navy of the United Kingdom that saw service during World War II. She was later converted into a Type 15 fast anti-submarine frigate, with the new pennant number F83. Ulster was the second vessel in Royal Navy history to have that name.
Raymond Leonard "Ray" Garthoff is a senior fellow at the Brookings Institution, a specialist on arms control, intelligence, the Cold War, NATO, and the former Soviet Union. He is a former U.S. Ambassador to Bulgaria, and has advised the U.S. State Department on treaties.
Willapa Bay is a large shallow body of water near the Pacific Ocean in southwestern Washington. For a number of years before modern roads were built in Pacific County, Washington, the bay was used as the means of travel around the county, by powered and unpowered craft. This article discusses steamboat navigation on Willapa Bay.
Michael Christopher "Topex" Robinson is a former Filipino professional basketball player and head coach for the Phoenix Super LPG Fuel Masters of the Philippine Basketball Association. He was drafted forty-fourth overall by the Tanduay Rhum Masters.
A Submarine Escape Training Tower is part of a facility used for training submariners in methods of emergency escape from a disabled submarine. It is a tall cylinder filled with water with several entrances at varying depths each simulating an airlock in a submarine. Since the 1930s, towers have been built for use by the Royal Navy, US Navy, Royal Australian Navy and in several other countries.
The second USS Orca (AVP-49) was a United States Navy seaplane tender in commission from 1944 to 1947 and from 1951 to 1960. She saw service during the latter stages of World War II and during the Cold War. In 1962 she was loaned to Ethiopia, where she served in the Ethiopian Navy as the training ship Ethiopia (A-01) until 1991. She was the Ethiopian Navy's largest ship until she was sold for scrapping in 1993.
The Ndjébbana language, also spelt Djeebbana and Ndjebanna and also known as Kunibidji, is a Burarran language spoken by the Gunavidji (Ndjebbana) people of North-central Arnhem Land in the Northern Territory of Australia.
Surgeon Vice Admiral Sir John Stuart Pepys Rawlins, was a Royal Navy officer and pioneer in the field of diving medicine.
The Type 291 radar was designed as a search radar for ships destroyer-sized and smaller in 1942. By the end of the Second World War it had been installed in almost every British and Commonwealth destroyer and escort ship as well as many submarines, naval trawlers, and motor torpedo boats. Some sets were furnished to the Soviet Union for their destroyers as a part of Lend-Lease.