1,491 research outputs found
MACRO results on atmospheric neutrinos
We discuss the final results of the MACRO experiment on atmospheric neutrino
oscillations. The data concern event topologies with average neutrino energies
of ~3 and ~50 GeV. Multiple Coulomb Scattering of the high energy muons was
used to estimate the neutrino energy event by event. The angular distributions,
the L/E_nu distribution, the particle ratios and the absolute fluxes all favor
nu_mu --> nu_tau oscillations with maximal mixing and Delta m^2 ~0.0023 eV^2.
Emphasis is given to measured ratios which are not affected by Monte Carlo (MC)
absolute normalization; a discussion is made on MC uncertainties. A preliminary
search for possible Lorentz invariance violation contributions to atmospheric
neutrino oscillations is presented and discussed.Comment: 4 pages, 6 figures. Paper presented at the NOW 2004 Workshop, Conca
Specchiulla, Otranto, Italy, September 200
Neutrino physics and astrophysics with the MACRO detector
After a brief presentation of the MACRO detector we discuss the data on
atmospheric neutrinos and neutrino oscillations, on high energy (E> 1 GeV)
neutrino astronomy, on indirect searches for WIMPs and low energy (E >7 MeV)
stellar collapse neutrinos.Comment: 8 pages, 7 figures. Invited paper at the Chacaltaya Meeting on Cosmic
Ray Physics, La Paz, 23-27 July, 200
B- and C-type low molecular weight glutenin subunits in tetraploid wheat germplasm
General knowledge acquisition entails the extraction of statistical regularities from the environment. At high levels of complexity, this may involve the extraction, and consolidation, of associative regularities across event memories. The underlying neural mechanisms would likely involve a hippocampo-neocortical dialog, as proposed previously for system-level consolidation. To test these hypotheses, we assessed possible differences in consolidation between associative memories containing cross-episodic regularities and unique associative memories. Subjects learned face-location associations, half of which responded to complex regularities regarding the combination of facial features and locations, whereas the other half did not. Importantly, regularities could only be extracted over hippocampus-encoded, associative aspects of the items. Memory was assessed both immediately after encoding and 48 h later, under fMRI acquisition. Our results suggest that processes related to system-level reorganization occur preferentially for regular associations across episodes. Moreover, the build-up of general knowledge regarding regular associations appears to involve the coordinated activity of the hippocampus and mediofrontal regions. The putative cross-talk between these two regions might support a mechanism for regularity extraction. These findings suggest that the consolidation of cross-episodic regularities may be a key mechanism underlying general knowledge acquisition
Fragmentation cross sections of Fe^{26+}, Si^{14+} and C^{6+} ions of 0.3-10 A GeV on CR39, polyethylene and aluminum targets
New measurements of the total and partial fragmentation cross sections in the
energy range 0.3-10 A GeV of Fe^{26+}, Si^{14+} and C^{6+} beams on
polyethylene, CR39 and aluminum targets are presented. The exposures were made
at Brookhaven National Laboratory (BNL), USA, and Heavy Ion Medical Accelerator
in Chiba (HIMAC), Japan. The CR39 nuclear track detectors were used to identify
the incident and survived beams and their fragments. The total fragmentation
cross sections for all targets are almost energy independent while they depend
on the target mass. The measured partial fragmentation cross sections are also
discussed.Comment: 4 pages, 5 eps figures. Talk given at the 24th International
Conference on Nuclear Tracks in Solids, Bologna, Italy, 1-5 September 200
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