منابع مشابه
Extinction learning, reconsolidation and the internal reinforcement hypothesis.
Retrieving a consolidated memory--by exposing an animal to the learned stimulus but not to the associated reinforcement--leads to two opposing processes: one that weakens the old memory as a result of extinction learning, and another that strengthens the old, already-consolidated memory as a result of some less well-understood form of learning. This latter process of memory strengthening is oft...
متن کاملK-Pg extinction: Reevaluation of the heat-fire hypothesis
[1] The global debris layer created by the end-Cretaceous impact at Chicxulub contained enough soot to indicate that the entire terrestrial biosphere had burned. Preliminary modeling showed that the reentry of ejecta would have caused a global infrared (IR) pulse sufficient to ignite global fires within a few hours of the Chicxulub impact. This heat pulse and subsequent fires explain the terres...
متن کاملThe Chicxulub asteroid impact and mass extinction at the Cretaceous-Paleogene boundary.
The Cretaceous-Paleogene boundary approximately 65.5 million years ago marks one of the three largest mass extinctions in the past 500 million years. The extinction event coincided with a large asteroid impact at Chicxulub, Mexico, and occurred within the time of Deccan flood basalt volcanism in India. Here, we synthesize records of the global stratigraphy across this boundary to assess the pro...
متن کاملDetermination of asteroid masses
The masses of the three largest asteroids: (1) Ceres, (2) Pallas and (4) Vesta were determined from gravitational perturbations exerted on respectively 25, 2, and 26 selected asteroids. These masses were calculated by means of the leastsquares method as weighted means of the values obtained separately from the perturbations on single asteroids. Special attention was paid to the selection of the...
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ژورنال
عنوان ژورنال: Science
سال: 1981
ISSN: 0036-8075,1095-9203
DOI: 10.1126/science.211.4483.648