Celestial navigationCelestial navigation, also known as astronavigation, is the practice of position fixing using stars and other celestial bodies that enables a navigator to accurately determine their actual current physical position in space or on the surface of the Earth without relying solely on estimated positional calculations, commonly known as "dead reckoning." Celestial navigation is performed without using satellite navigation or other similar modern electronic or digital positioning means.
Navigation systemA navigation system is a computing system that aids in navigation. Navigation systems may be entirely on board the vehicle or vessel that the system is controlling (for example, on the ship's bridge) or located elsewhere, making use of radio or other signal transmission to control the vehicle or vessel. In some cases, a combination of these methods is used.
Articular processesThe articular processes or zygapophyses (Greek ζυγον = "yoke" (because it links two vertebrae) + απο = "away" + φυσις = "process") of a vertebra are projections of the vertebra that serve the purpose of fitting with an adjacent vertebra. The actual region of contact is called the articular facet. Articular processes spring from the junctions of the pedicles and laminæ, and there are two right and left, and two superior and inferior. These stick out of an end of a vertebra to lock with a zygapophysis on the next vertebra, to make the backbone more stable.
Kirschner wireKirschner wires or K-wires or pins are sterilized, sharpened, smooth stainless steel pins. Introduced in 1909 by Martin Kirschner, the wires are now widely used in orthopedics and other types of medical and veterinary surgery. They come in different sizes and are used to hold bone fragments together (pin fixation) or to provide an anchor for skeletal traction. The pins are often driven into the bone through the skin (percutaneous pin fixation) using a power or hand drill. They also form part of the Ilizarov apparatus.
Pott's diseasePott's disease, named for British surgeon Percivall Pott who first described the symptoms in 1799, also known as Pott disease is tuberculosis of the spine, usually due to haematogenous spread from other sites, often the lungs. The lower thoracic and upper lumbar vertebrae areas of the spine are most often affected. It causes a kind of tuberculous arthritis of the intervertebral joints. The infection can spread from two adjacent vertebrae into the adjoining intervertebral disc space.
Niche marketA niche market is the subset of the market on which a specific product is focused. The market niche defines the product features aimed at satisfying specific market needs, as well as the price range, production quality and the demographics that it is intended to target. It is also a small market segment. Sometimes, a product or service can be entirely designed to satisfy a niche market. Not every product can be defined by its market niche. The niche market is highly specialized, and aiming to survive among the competition from numerous super companies.
HoloLens 2Microsoft HoloLens 2 is a mixed reality head-mounted display developed and manufactured by Microsoft. It is the successor to the original Microsoft HoloLens. The first variant of the device, The HoloLens 2 enterprise edition, debuted on February 24, 2019. This was followed by a developer edition that was announced on May 2, 2019. The HoloLens 2 was subsequently released in limited numbers on November 7, 2019. The HoloLens 2 was announced by lead HoloLens developer Alex Kipman on February 24, 2019 at Mobile World Congress (MWC) in Barcelona, Spain.
MicrosoftMicrosoft Corporation is an American multinational technology corporation headquartered in Redmond, Washington. Microsoft's best-known software products are the Windows line of operating systems, the Microsoft 365 suite of productivity applications, and the Internet Explorer and Edge web browsers. Its flagship hardware products are the Xbox video game consoles and the Microsoft Surface lineup of touchscreen personal computers. Microsoft ranked No.
Lunar distance (navigation)In celestial navigation, lunar distance is the angular distance between the Moon and another celestial body. The lunar distances method uses this angle, also called a lunar, and a nautical almanac to calculate Greenwich time if so desired, or by extension any other time. That calculated time can be used in solving a spherical triangle. The theory was first published by Johannes Werner in 1524, before the necessary almanacs had been published. A fuller method was published in 1763 and used until about 1850 when it was superseded by the marine chronometer.
Polynesian navigationPolynesian navigation or Polynesian wayfinding was used for thousands of years to enable long voyages across thousands of kilometers of the open Pacific Ocean. Polynesians made contact with nearly every island within the vast Polynesian Triangle, using outrigger canoes or double-hulled canoes. The double-hulled canoes were two large hulls, equal in length, and lashed side by side. The space between the paralleled canoes allowed for storage of food, hunting materials, and nets when embarking on long voyages.
