Finding the engram.

Many attempts have been made to localize the physical trace of a memory, or engram, in the brain. However, until recently, engrams have remained largely elusive. In this Review, we develop four defining criteria that enable us to critically assess the recent progress that has been made towards finding the engram. Recent \u27capture\u27 studies use novel approaches to tag populations of neurons that are active during memory encoding, thereby allowing these engram-associated neurons to be manipulated at later times. We propose that findings from these capture studies represent considerable progress in allowing us to observe, erase and express the engram

A spin analysis of the 4 pi channels produced in central pp interactions at 450 GeV/c

The reactions pp –> p(f)(X-0)p(s), where X-0 is observed decaying to pi(0)pi(0)pi(0)pi(0), pi(+)pi(-)pi(+)pi(-) and pi(+)pi(-)pi(0)pi(0), have been studied at 450 GeV/c. There is evidence for an a(2)(1320)pi decay mode of the eta(2)(1645) and eta(2)(1870) in the pi(+)pi(-)pi(0)pi(0) and pi(+)pi(-)pi(+)pi(-) find states. The f(2)(1950) is consistent with being a single resonance with a dominant f(2)(1270)pi pi decay mode. The f(0)(1370) is found to decay dominantly to rho rho while the f(0)(1500) is found to decay to rho rho and sigma sigma. (C) 2000 Published by Elsevier Science B.V. All rights reserved

THE SLOW POSITION-SENSITIVE TIME-OF-FLIGHT DETECTOR OF THE GAMS NA 12/2 EXPERIMENT OF CERN

A large time-of-flight detector has been built by the GAMS NA12/2 experiment at CERN. It surrounds a 60 cm long liquid hydrogen target. With a time resolution better than sigma = 350 ps, pion/proton separation is achieved up to a 800 MeV/c momentum

A study of the eta eta ` and eta `eta ` channels produced in central pp interactions at 450 GeV/c

The reactions pp –> p(f)(X-0)p(s), where X-0 is observed decaying to eta eta’ and eta’eta’, have been studied at 450 GeV/c. This is the first time that these channels have been observed in central production and only the second time that the eta’eta’ channel has been observed in any production mechanism. In the eta eta’ channel there is evidence for the f(0)(1500) and a peak at 1.95 GeV. The eta’eta’ channel shows a peak at threshold which is compatible with having J(PC) = 2(++) and spin projection J(Z) = 0. (C) 2000 Published by Elsevier Science B.V. All rights reserved

A study of the f(0)(1370), f(0)(1500), f(0)(2000) and f(2)(1950) observed in the centrally produced 4 pi final states

{The production and decay properties of the f(0)(1370), f(0)(1500), f(0)(2000) and f(2)(1950) have been studied in central pp interactions at 450 GeV/c. The dP(T), phi and \textbackslash{}t\textbackslash{} distributions of these resonances are presented. For the J= 0 states, the f(0)(1370) and f(0)(2000) have similar dP(T) and phi dependences. These are different to the dP(T) and phi dependences of the f(0)(980), f(0)(1500) and f(0)(1710). For the J = 2 states the f(2)(1950) has different dependences to the f(2)(1270) and f(2)(1520). This shows that the dP(T) and phi dependences are not just J phenomena. (C) 2000 Published by Elsevier Science B,V. All rights reserved.

GAMS RESULTS ON THE OMEGA-PI(0) SYSTEM

The first results on the omega-pi-0 system produced in the charge-exchange reaction of pi--p scattering at 38 GeV/c and 100 GeV/c are presented. The omega-pi-0 mass spectrum shows, alongside with the well-known b1(0) (1235) and rho-3(0) (1690) mesons, a new neutral state with mass 2200 +/- 20 MeV and width 260 +/- 50 MeV. This meson, X(2200), is produced like rho-3 through one-pion exchange. X(2200) is a candidate for the 1-- multiplet, and its possible interpretation is a 2(3)D1 excitation of the rho-0. Its production cross section at 3 S GeV/c is equal to sigma(pi--p --> Xn) . BR (X --> omega-pi-0) = 120 +/- 25 nb. Cross sections for b1 and rho-3 have also been measured. The energy dependences have been determined