Monday, February 3, 2020

Corona Viruse



Coronaviruses are a group of viruses that cause diseases in mammals and birds. In humans, the viruses cause respiratory infections – including the common cold – which are typically mild. Rarer forms such as SARS, MERS and the novel coronavirus causing the 2019–20 Wuhan coronavirus outbreak can be lethal. In cows and pigs coronaviruses cause diarrhea. In chickens they cause an upper respiratory disease. There are no vaccines or antiviral drugs that are approved for prevention or treatment.

Coronaviruses are viruses in the subfamily Orthocoronavirinae in the family Coronaviridae, in the order Nidovirales. Coronaviruses are enveloped viruses with a positive-sense single-stranded RNA genome and with a nucleocapsid of helical symmetry. The genomic size of coronaviruses ranges from approximately 26 to 32 kilobases, the largest for an RNA virus.

The name "coronavirus" is derived from the Latin corona, meaning crown or halo, which refers to the characteristic appearance of the virus particles (virions): they have a fringe reminiscent of a royal crown or of the solar corona.


Coronaviruses were discovered in the 1960s. The earliest ones discovered were infectious bronchitis virus in chickens and two viruses from the nasal cavities of human patients with the common cold that were subsequently named human coronavirus 229E and human coronavirus OC43. Other members of this family have since been identified, including SARS-CoV in 2003, HCoV NL63 in 2004, HKU1 in 2005, MERS-CoV in 2012, and 2019-nCoV in 2019; most of these have been involved in serious respiratory tract infections.

Drone



An unmanned aerial vehicle (UAV) (or uncrewed aerial vehicle,commonly known as a drone) is an aircraft without a human pilot on board and a type of unmanned vehicle. UAVs are a component of an unmanned aircraft system (UAS); which include a UAV, a ground-based controller, and a system of communications between the two. The flight of UAVs may operate with various degrees of autonomy: either under remote control by a human operator or autonomously by onboard computers.

Compared to crewed aircraft, UAVs were originally used for missions too "dull, dirty or dangerous" for humans. While they originated mostly in military applications, their use is rapidly expanding to commercial, scientific, recreational, agricultural, and other applications,such as policing and surveillance, product deliveries, aerial photography, smuggling, and drone racing. Civilian UAVs now vastly outnumber military UAVs, with estimates of over a million sold by 2015.[citation needed]

The term drone, more widely used by the public, was coined in reference to the early remotely-flown target aircraft used for practice firing of a battleship's guns, and the term was first used with the 1920s Fairey Queen and 1930's de Havilland Queen Bee target aircraft. These two were followed in service by the similarly-named Airspeed Queen Wasp and Miles Queen Martinet, before ultimate replacement by the GAF Jindivik.

The term unmanned aircraft system (UAS) was adopted by the United States Department of Defense (DoD) and the United States Federal Aviation Administration in 2005 according to their Unmanned Aircraft System Roadmap 2005–2030.[8] The International Civil Aviation Organization (ICAO) and the British Civil Aviation Authority adopted this term, also used in the European Union's Single-European-Sky (SES) Air-Traffic-Management (ATM) Research (SESAR Joint Undertaking) roadmap for 2020.[9] This term emphasizes the importance of elements other than the aircraft. It includes elements such as ground control stations, data links and other support equipment. A similar term is an unmanned-aircraft vehicle system (UAVS), remotely piloted aerial vehicle (RPAV), remotely piloted aircraft system (RPAS).

A UAV is defined as a "powered, aerial vehicle that does not carry a human operator, uses aerodynamic forces to provide vehicle lift, can fly autonomously or be piloted remotely, can be expendable or recoverable, and can carry a lethal or nonlethal payload".Therefore, missiles are not considered UAVs because the vehicle itself is a weapon that is not reused, though it is also uncrewed and in some cases remotely guided.


Under new regulations which came into effect June 1, 2019, the term RPAS (Remotely Piloted Aircraft System) has been adopted by the Canadian Government to mean "a set of configurable elements consisting of a remotely piloted aircraft, its control station, the command and control links and any other system elements required during flight operation".

The relation of UAVs to remote controlled model aircraft is unclear.[citation needed] UAVs may or may not include model aircraft. Some jurisdictions base their definition on size or weight; however, the US Federal Aviation Administration defines any uncrewed flying craft as a UAV regardless of size. For recreational uses, a drone (as opposed to a UAV) is a model aircraft that has first-person video, autonomous capabilities, or both.