26 research outputs found
Probability of local bifurcation type from a fixed point: A random matrix perspective
Results regarding probable bifurcations from fixed points are presented in
the context of general dynamical systems (real, random matrices), time-delay
dynamical systems (companion matrices), and a set of mappings known for their
properties as universal approximators (neural networks). The eigenvalue spectra
is considered both numerically and analytically using previous work of Edelman
et. al. Based upon the numerical evidence, various conjectures are presented.
The conclusion is that in many circumstances, most bifurcations from fixed
points of large dynamical systems will be due to complex eigenvalues.
Nevertheless, surprising situations are presented for which the aforementioned
conclusion is not general, e.g. real random matrices with Gaussian elements
with a large positive mean and finite variance.Comment: 21 pages, 19 figure
Hadron Energy Reconstruction for the ATLAS Calorimetry in the Framework of the Non-parametrical Method
This paper discusses hadron energy reconstruction for the ATLAS barrel
prototype combined calorimeter (consisting of a lead-liquid argon
electromagnetic part and an iron-scintillator hadronic part) in the framework
of the non-parametrical method. The non-parametrical method utilizes only the
known ratios and the electron calibration constants and does not require
the determination of any parameters by a minimization technique. Thus, this
technique lends itself to an easy use in a first level trigger. The
reconstructed mean values of the hadron energies are within of the
true values and the fractional energy resolution is . The value of the ratio
obtained for the electromagnetic compartment of the combined calorimeter is
and agrees with the prediction that for this
electromagnetic calorimeter. Results of a study of the longitudinal hadronic
shower development are also presented. The data have been taken in the H8 beam
line of the CERN SPS using pions of energies from 10 to 300 GeV.Comment: 33 pages, 13 figures, Will be published in NIM
Performance of the ATLAS Electromagnetic Calorimeter End-cap Module 0
The construction and beam test results of the ATLAS electromagnetic end-cap calorimeter pre-production module 0 are presented. The stochastic term of the energy resolution is between 10% GeV^1/2 and 12.5% GeV^1/2 over the full pseudorapidity range. Position and angular resolutions are found to be in agreement with simulation. A global constant term of 0.6% is obtained in the pseudorapidity range 2.5 < eta < 3.2 (inner wheel)
Performance of the ATLAS electromagnetic calorimeter end-cap module 0
The construction and beam test results of the ATLAS electromagnetic end-cap calorimeter pre-production module 0 are presented. The stochastic term of the energy resolution is between 10% GeV^1/2 and 12.5% GeV^1/2 over the full pseudorapidity range. Position and angular resolutions are found to be in agreement with simulation. A global constant term of 0.6% is obtained in the pseudorapidity range 2.5 eta 3.2 (inner wheel)
A new global Earth gravity field model from satellite orbit perturbations for support of geodetic/geophysical and oceanographic satellite missions Reference frame and low degree gravity field solution (GRIM5 - step 1)
GFZ Potsdam and GRGS, Toulouse, are preparing in a joint effort of a new generation of Earth gravity field models called GRIM5. Based upon the analyses of gravitational induced satellite orbit perturbations, satellite tracking data obtained from numerous satellites are going to be exploited to solve simultaneously for gravitational and ocean tide potential and tracking station positions parameters. The GRIM5 task was split up into two steps. Within step1 the algorithm and software development was accomplished to establish up-to-date computational standards which considerably differ from the former GRIM4 standards. In particular, emphasize was laid on the consideration of temporal gravitational and reference system related tidal and on-tidal variations due to Earth rotation, and ocean and atmosphere dynamics. The implementation of the new computational standards was numerically validated by adjusting for a new reference frame (195 tracking station positions and velocities), low degree gravitational coefficients and selected secular rates of change, for cyclic geocentre variations and pole tide related Love numbers in a simultaneous solution derived from laser, DORIS, PRARE and GPS-SST tracking data of 9 satellites. From this solution, which is called GRIM5-Step1 and which is documented and discussed in this report, sound expertise on the treatment of satellite tracking data for precise orbit and Earth parameter recovery within the new computational and software environment could be acquired to enter into the Step2 processing for a complete GRIM5 Earth gravity field model solution. This model shall be created in preparation of the coming gravity field dedicated satellite missions, like CHAMP, and altimeter missions like Jason. (orig.)Summary in German and FrenchSIGLEAvailable from TIB Hannover: RR 6134(98/18) / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekBundesministerium fuer Bildung, Wissenschaft, Forschung und Technologie, Bonn (Germany); DLR Deutsches Zentrum fuer Luft- und Raumfahrt e.V., Bonn (Germany)DEGerman
Adaptation to Abundant Low Quality Food Improves the Ability to Compete for Limited Rich Food in Drosophila melanogaster.
The rate of food consumption is a major factor affecting success in scramble competition for a limited amount of easy-to-find food. Accordingly, several studies report positive genetic correlations between larval competitive ability and feeding rate in Drosophila; both become enhanced in populations evolving under larval crowding. Here, we report the experimental evolution of enhanced competitive ability in populations of D. melanogaster previously maintained for 84 generations at low density on an extremely poor larval food. In contrast to previous studies, greater competitive ability was not associated with the evolution of higher feeding rate; if anything, the correlation between the two traits across lines tended to be negative. Thus, enhanced competitive ability may be favored by nutritional stress even when competition is not intense, and competitive ability may be decoupled from the rate of food consumption