collapse

[Date: 1700-1800; Language: Latin; Origin: collapsus, past participle of collabi, from com- ( COM-) + labi 'to fall, slide']

In medical science, collapse is a sudden and often unannounced loss of postural [relating to the way you sit or stand] tone [how firm and strong your muscles or skin are] (going weak), often but not necessarily accompanied by loss of consciousness. If the episode [发作] is accompanied by a loss of consciousness, the term syncope [晕厥] is used. The main causes are cardiac (e.g. due to irregular heart beat, low blood pressure), seizures or a psychological cause. The main tool in distinguishing the causes is careful history on the events before, during and after the collapse, from the patient as well as from any possible witnesses. Other investigations may be performed to further strengthen the diagnosis, but many of these have a low yield.

Ecological collapse refers to a situation where an ecosystem suffers a drastic, possibly permanent, reduction in carrying capacity for all organisms, often resulting in mass extinction. Usually, an ecological collapse is precipitated by a disastrous event occurring on a short time scale. Ecological collapse can be considered as a consequence of ecosystem collapse on the biotic elements that depended on the original ecosystem.

Economic collapse is any of a broad range of bad economic conditions, ranging from a severe, prolonged depression with high bankruptcy rates and high unemployment (such as the Great Depression of the 1930s), to a breakdown in normal commerce caused by hyperinflation (such as in Weimar Germany in the 1920s), or even an economically caused sharp rise in the death rate and perhaps even a decline in population (such as in countries of the former USSR in the 1990s). Often economic collapse is accompanied by social chaos, civil unrest and a breakdown of law and order. There are few well documented cases of economic collapse. One of the best documented cases of collapse or near collapse is the Great Depression, the causes of which are still being debated. "To understand the Great Depression is the Holy Grail of macroeconomics." —Ben Bernanke (1995)

Holy Grail
1. 圣杯
2. sth that people want very much, but which is very difficult or impossible to achieve

Societal [relating to a particular society] collapse (also known as civilizational collapse) is the fall of a complex human society characterized by the loss of cultural identity and of socioeconomic complexity, the downfall of government, and the rise of violence.[1] Possible causes of a societal collapse include natural catastrophe, war, pestilence, famine, and depopulation. A collapsed society may revert to a more primitive state, be absorbed into a stronger society, or completely disappear.

Gravitational collapse is the contraction of an astronomical object due to the influence of its own gravity, which tends to draw matter inward toward the centre of gravity. Gravitational collapse is a fundamental mechanism for structure formation in the universe. Over time an initial, relatively smooth distribution of matter will collapse to form pockets of higher density, typically creating a hierarchy of condensed structures such as clusters of galaxies, stellar groups, stars and planets.

In quantum mechanics, wave function collapse occurs when a wave function—initially in a superposition of several eigenstates—reduces to a single eigenstate due to interaction with the external world. This interaction is called an "observation". 在量子力学中，当最初处于多个本征态叠加的波函数由于与外部世界的相互作用而降低为单个本征态时，波函数崩溃就会发生。这种互动被称为“观察”。

六级/考研单词: gradual, seldom, tentative, episode, irregular, psychology, farther, diagnose, yield, situate, ecosystem, drastic, perpetual, organism, extinct, prolong, depress, bankrupt, breakdown, norm, commerce, chaos, holy, catastrophe, famine, reverse, primitive, astronomy, gravitation, outward, hierarchy, condense, cluster, galaxy, planet, mechanic, interact