143 research outputs found
Motion of vortices implies chaos in Bohmian mechanics
Bohmian mechanics is a causal interpretation of quantum mechanics in which
particles describe trajectories guided by the wave function. The dynamics in
the vicinity of nodes of the wave function, usually called vortices, is regular
if they are at rest. However, vortices generically move during time evolution
of the system. We show that this movement is the origin of chaotic behavior of
quantum trajectories. As an example, our general result is illustrated
numerically in the two-dimensional isotropic harmonic oscillator.Comment: 7 pages 5 figure
Robust transitivity and domination for endomorphisms displaying critical points
We show that robustly transitive endomorphisms of a closed manifolds must
have a non-trivial dominated splitting or be a local diffeomorphism. This
allows to get some topological obstructions for the existence of robustly
transitive endomorphisms. To obtain the result we must understand the structure
of the kernel of the differential and the recurrence to the critical set of the
endomorphism after perturbation.Comment: We rewrote Lemmas 2.7 and 4.7 in order to be clearer. we also would
like to thanks the referee for their suggestion and comment
Vortex interaction, chaos and quantum probabilities
The motion of a single vortex is able to originate chaos in the quantum
trajectories defined in Bohm's interpretation of quantum mechanics. In this
Letter, we show that this is also the case in the general situation, in which
many interacting vortices exist. This result gives support to recent attempts
in which Born's probability rule is derived in terms of an irreversible time
evolution to equilibrium, rather than being postulated.Comment: 4 pages, 4 figure
Vortices and chaos in the quantum fluid
The motion of a single vortex originates chaos in the quantum fluid defined in Bohm\u27s interpretation of quantum mechanics. Here we analize this situation in a very simple case: one single vortex in a rectangular billiard
Bifurcations of periodic and chaotic attractors in pinball billiards with focusing boundaries
We study the dynamics of billiard models with a modified collision rule: the
outgoing angle from a collision is a uniform contraction, by a factor lambda,
of the incident angle. These pinball billiards interpolate between a
one-dimensional map when lambda=0 and the classical Hamiltonian case of elastic
collisions when lambda=1. For all lambda<1, the dynamics is dissipative, and
thus gives rise to attractors, which may be periodic or chaotic. Motivated by
recent rigorous results of Markarian, Pujals and Sambarino, we numerically
investigate and characterise the bifurcations of the resulting attractors as
the contraction parameter is varied. Some billiards exhibit only periodic
attractors, some only chaotic attractors, and others have coexistence of the
two types.Comment: 30 pages, 17 figures. v2: Minor changes after referee comments.
Version with some higher-quality figures available at
http://sistemas.fciencias.unam.mx/~dsanders/publications.htm
The ESCRT-III machinery participates in the production of extracellular vesicles and protein export during Plasmodium falciparum infection
Malaria is a disease caused by Plasmodium parasites that is still a leading cause of death in many low-income countries, and for which currently available therapeutic strategies are not succeeding in its control, let alone eradication. An interesting feature observed after Plasmodium invasion is the increase of extracellular vesicles (EVs) generated by parasitized red blood cells (pRBCs), which lack a vesicular trafficking that would explain EV production. Here, by combining different approaches, we demonstrated the participation of the endosomal sorting complex required for transport (ESCRT) machinery from Plasmodium falciparum in the production of EVs in pRBCs. Moreover, we were able to detect ESCRT-III proteins adjacent to the membrane of the host and in EVs purified from a pRBC culture, which shows the export of these proteins and their participation in EV production. Finally, the disruption of an ESCRT-III associated gene, Pfvps60, led to a significant reduction in the amount of EVs. Altogether, these results confirm ESCRT-III participation in EV production and provide novel information on the P. falciparum protein export mechanisms, which can be used for the development of new therapeutic strategies against malaria, based on the disruption of EV formation and trafficking
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