Search for: All records

Abstract Terrestrial Gamma‐ray Flashes (TGFs) are ten‐to‐hundreds of microsecond bursts of gamma‐rays produced when electrons in strong electric fields in thunderclouds are accelerated to relativistic energies. Space instruments have observed TGFs with source photon brightness down to ∼10¹⁷–10¹⁶. Based on space and aircraft observations, TGFs have been considered rare phenomena produced in association with very few lightning discharges. Space observations associated with lightning ground observations in the radio band have indicated that there exists a population of dimmer TGFs. Here we show observations of TGFs from aircraft altitude that were not detected by a space instrument viewing the same area. The TGFs were found through Monte Carlo modeling to be associated with 10¹⁵–10¹²photons at source, which is several orders of magnitude below what can be seen from space. Our results suggest that there exists a significant population of TGFs that are too weak to be observed from space. 

Listening to a speaker selectively practicing previously encoded information leads to better memory for the practiced information, but at the same time results in induced forgetting of related memories. These effects have been found to occur due to the concurrent, and covert, retrieval of information on the part of the listener. Using a modified version of the method of serial reproduction (Bartlett, 1932), this study explored the degree to which rehearsal and retrieval-induced forgetting effects propagated in 64 3-person-chains of connected participants. We manipulated the degree of concurrent retrieval from the part of the listener by activating high and low relational motivations during the listening task. We showed that the degree of propagation of retrieval-induced forgetting was larger when concurrent retrieval was activated (high-relational motivation) than when concurrent retrieval was attenuated (low-relational motivation). This study provides a framework that aims to bridge between micro-level cognitive phenomena and macro-level social dynamics.