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A train is a form of rail transport consisting of a series of connected vehicles that generally run along a railroad (or railway) track to transport passengers or cargo (also known as "freight" or "goods"). The word train comes from the Old French trahiner, derived from the Latin trahere meaning 'to pull, to draw'.Motive power for a train is provided by a separate locomotive or individual motors in a self-propelled multiple unit. The term "engine" is often used as an alternative to locomotive. Although historically steam propulsion dominated, the most common types of locomotive are diesel and electric, the latter supplied by overhead wires or additional rails. Trains can also be hauled by horses, pulled by engine or water-driven cable or wire winch, run downhill using gravity, or powered by pneumatics, gas turbines or electric batteries.
The track usually consists of two running rails with a fixed spacing, which may be supplemented by additional rails such as electric conducting rails ("third rail") and rack rails. Monorails and maglev guideways are also occasionally used.Passenger trains include passenger-carrying vehicles and can often be very long and fast. High-speed rail systems began expanding rapidly in the late 20th century, and this remains a major subject of further development. The term "light rail" is sometimes used to refer to a modern tram system, but it may also mean an intermediate form between a tram and a train, similar to a heavy rail rapid transit system.
Freight (goods) trains use freight cars (or wagons/trucks) to transport goods or materials (cargo). It is possible to carry passengers and freight in the same train using a mixed consist.
Rail cars and machinery that are used for the maintenance and repair of tracks, are termed "maintenance of way" equipment; these may be assembled into maintenance of way trains. Similarly, dedicated trains may be used to provide support services to stations along a train line, such as garbage or revenue collection.Unemployment, according to the OECD (Organisation for Economic Co-operation and Development), is persons above a specified age (usually 15) not being in paid employment or self-employment but currently available for work during the reference period.Unemployment is measured by the unemployment rate, which is the number of people who are unemployed as a percentage of the labour force (the total number of people employed added to those unemployed).Unemployment can have many sources, such as the following:
new technologies and inventions
the status of the economy, which can be influenced by a recession
competition caused by globalization and international trade
policies of the government
regulation and marketUnemployment and the status of the economy can be influenced by a country through, for example, fiscal policy. Furthermore, the monetary authority of a country, such as the central bank, can influence the availability and cost for money through its monetary policy.
In addition to theories of unemployment, a few categorisations of unemployment are used for more precisely modelling the effects of unemployment within the economic system. Some of the main types of unemployment include structural unemployment, frictional unemployment, cyclical unemployment, involuntary unemployment and classical unemployment. Structural unemployment focuses on foundational problems in the economy and inefficiencies inherent in labor markets, including a mismatch between the supply and demand of laborers with necessary skill sets. Structural arguments emphasize causes and solutions related to disruptive technologies and globalization. Discussions of frictional unemployment focus on voluntary decisions to work based on individuals' valuation of their own work and how that compares to current wage rates added to the time and effort required to find a job. Causes and solutions for frictional unemployment often address job entry threshold and wage rates.
According to the UN's International Labour Organization (ILO), there were 172 million people worldwide (or 5% of the reported global workforce) without work in 2018.Because of the difficulty in measuring the unemployment rate by, for example, using surveys (as in the United States) or through registered unemployed citizens (as in some European countries), statistical figures such as the employment-to-population ratio might be more suitable for evaluating the status of the workforce and the economy if they were based on people who are registered, for example, as taxpayers.A people is any plurality of persons considered as a whole.
Used in politics and law it is a term to refer to the collective or community of an ethnic group, a nation, to the public or common mass of people of a polity. As such it is a concept of human rights law, international law as well as constitutional law, particularly used for claims of popular sovereignty.The platypus (Ornithorhynchus anatinus), sometimes referred to as the duck-billed platypus, is a semiaquatic, egg-laying mammal endemic to eastern Australia, including Tasmania. The platypus is the sole living representative of its family (Ornithorhynchidae) and genus (Ornithorhynchus), though a number of related species appear in the fossil record.
Together with the four species of echidna, it is one of the five extant species of monotremes, the only mammals that lay eggs instead of giving birth to live young. Like other monotremes, it senses prey through electrolocation. It is one of the few species of venomous mammals, as the male platypus has a spur on the hind foot that delivers a venom, capable of causing severe pain to humans. The unusual appearance of this egg-laying, duck-billed, beaver-tailed, otter-footed mammal baffled European naturalists when they first encountered it, and the first scientists to examine a preserved platypus body (in 1799) judged it a fake, made of several animals sewn together.
The unique features of the platypus make it an important subject in the study of evolutionary biology, and a recognisable and iconic symbol of Australia. It is culturally significant to several Aboriginal peoples of Australia, who also used to hunt the animal for food. It has appeared as a mascot at national events and features on the reverse of the Australian twenty-cent coin, and the platypus is the animal emblem of the state of New South Wales. Until the early 20th century, humans hunted the platypus for its fur, but it is now protected throughout its range. Although captive-breeding programs have had only limited success, and the platypus is vulnerable to the effects of pollution, it is not under any immediate threat.
As of 2020, the platypus is a legally protected species in all states where it occurs. It is listed as an endangered species in South Australia and Victoria and has been recommended for listing in New South Wales. The species is classified as a near-threatened species by the IUCN, but a November 2020 report has recommended that it is upgraded to threatened species under the federal EPBC Act, due to habitat destruction and declining numbers in all states.
שפה מקורית | ???core.languages.en_GB??? |
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מזהי עצם דיגיטלי (DOIs) | |
סטטוס פרסום | ???researchoutput.status.published??? - 2021 |
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שם | xinhuanet.com |
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