RESUMEN
Numerical simulations show that, at the onset of Anderson localization, the momentum distribution of a coherent wave packet launched inside a random potential exhibits, in the forward direction, a novel interference peak that complements the coherent backscattering peak. An explanation of this phenomenon in terms of maximally crossed diagrams predicts that the signal emerges around the localization time and grows on the scale of the Heisenberg time associated with the localization volume. Together, coherent back and forward scattering provide evidence for the occurrence of Anderson localization.
RESUMEN
Results of karyological study of Picea ajanensis (Lindl. et Gord.) Fisch. ex Carr examined from 13 provenances are presented. In addition to the cytotypes with typical chromosome number (2n = 24), P. ajanensis displays cytotypes with one or two B-chromosomes (2n = 24 + 1 - 2B). Among A-chromosomes, there are 8 pairs of long metacentrics and 4 pairs of shorter meta- or submetacentrics. Among B-chromosomes there are two types of chromosomes: metacentric (B1) and submetacentric (B2) ones. There are many nucleolar chromosomes. Several chromosomes have secondary constrictions. Patterns of B-chromosome distribution within P. ajanensis are have been discussed.
Asunto(s)
Cromosomas de las Plantas/genética , Picea/genética , Cariotipificación , Siberia , Especificidad de la EspecieRESUMEN
We theoretically consider the formation of bright solitons in a mixture of Bose and Fermi degenerate gases. While we assume the forces between atoms in a pure Bose component to be effectively repulsive, their character can be changed from repulsive to attractive in the presence of fermions provided the Bose and Fermi gases attract each other strongly enough. In such a regime the Bose component becomes a gas of effectively attractive atoms. Hence, generating bright solitons in the bosonic gas is possible. Indeed, after a sudden increase of the strength of attraction between bosons and fermions (realized by using a Feshbach resonance technique or by firm radial squeezing of both samples) soliton trains appear in the Bose-Fermi mixture.