55 research outputs found
Typologie des eaux de surface du bassin du Sebou par multi-approche : corrélation entre indice biologique global des réseaux de contrôle et de surveillance (IBG-RCS) et l’approche physicochimique et microbiologique
L’étude consiste en l’utilisation de la démarche biologique, particulièrement les indices IBGN et IBG-RCS, pour montrer l’évolution de la qualité biologique des eaux de surface du bassin du Sebou dans la période 2009-2011. La caractérisation physicochimique/microbiologique de la qualité des eaux de surface et la caractérisation biologique moyennant l’indice biocénotique IBG-RCS de l’an 2011ont fait l’objet d’un traitement statistique. Les résultats obtenus montrent une certaine amélioration dans la qualité des eaux de surface du bassin d’étude. L’analyse statistique a montré la formation de deux groupes corrélés négativement, le premier composé de l’oxygène dissous et l’indice IBG-RCS alors que le deuxième est formé des paramètres révélateurs de pollution organique (DBO5, DCO, NH4+, Phosphate Total PT et coliformes fécaux : CF).Mots-clés : Bassin Hydraulique du Sebou, indice IBG-RCS, qualité - biologique, macro-invertébrés, qualité physicochimique.Sebou’s water surface multi-approaches typology: correlation between the global biological index of control and surveillance networks (IBG-RCS) and the physicochemical/microbiological approachThe study consists of using the biological approach, especially the IBGN and the IBG-RCS indexes, to show the evolution of the biological surface waters quality of the Sebou basin in the period of 2009-2011. The physicochemical/microbiological surface waters quality characterization and the biological characterization (IBG-RCS index) of the year 2011 were the subject of a statistical processing. The results showed some improvement in surface waters quality. The statistical analysis showed the formation of two negatively correlated groups, the first consisting of dissolved oxygen and the IBG-RCS index while the second consists of the parameters indicative of pollution (BOD5, COD, NH4+, PT and CF).Keywords : hydraulic basin of Sebou, IBG-RCS index, biological quality, macroinvertebrates, physicochimical quality
Effect of electromagnetic fields on the creation of scalar particles in a flat Robertson-Walker space-time
The influence of electromagnetic fields on the creation of scalar particles
from vacuum in a flat Robertson-Walker space-time is studied. The Klein Gordon
equation with varying electric field and constant magnetic one is solved. The
Bogoliubov transformation method is applied to calculate the pair creation
probability and the number density of created particles. It is shown that the
electric field amplifies the creation of scalar particles while the magnetic
field minimizes it.Comment: Important modifications, 20 pages, To appear in Eurpean Physical
Journal C. arXiv admin note: text overlap with arXiv:1108.033
Path integral solution for an angle-dependent anharmonic oscillator
We have given a straightforward method to solve the problem of noncentral
anharmonic oscillator in three dimensions. The relative propagator is presented
by means of path integrals in spherical coordinates. By making an adequate
change of time we were able to separate the angular motion from the radial one.
The relative propagator is then exactly calculated. The energy spectrum and the
corresponding wave functions are obtained.Comment: Corrected typos and mistakes, To appear in Communications in
Theoretical Physic
Any l-state improved quasi-exact analytical solutions of the spatially dependent mass Klein-Gordon equation for the scalar and vector Hulthen potentials
We present a new approximation scheme for the centrifugal term to obtain a
quasi-exact analytical bound state solutions within the framework of the
position-dependent effective mass radial Klein-Gordon equation with the scalar
and vector Hulth\'{e}n potentials in any arbitrary dimension and orbital
angular momentum quantum numbers The Nikiforov-Uvarov (NU) method is used
in the calculations. The relativistic real energy levels and corresponding
eigenfunctions for the bound states with different screening parameters have
been given in a closed form. It is found that the solutions in the case of
constant mass and in the case of s-wave () are identical with the ones
obtained in literature.Comment: 25 pages, 1 figur
Saturation of coupling of collective levels in optical model calculations of even-even actinides
Saturation of the coupling-scheme is studied in dispersive optical model calculations of nucleon induced reactions on 238UÂ target. Recently derived potential that is based on a soft-rotator-model (SRM) description of the collective levels of the target nucleus with volume conservation is used. It is show that calculated direct excitation cross sections of all considered non-GS bands levels are larger than the 4+ GS band level excitation, and can't be ignored in coupled-channel calculations. SRM couplings of 21 levels constitute a saturated coupling scheme that allows a precise calculation of the compound-nucleus (CN) formation cross sections up to several MeV
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