Single File Diffusion of particles with long ranged interactions: damping and finite size effects

We study the Single File Diffusion (SFD) of a cyclic chain of particles that cannot cross each other, in a thermal bath, with long ranged interactions, and arbitrary damping. We present simulations that exhibit new behaviors specifically associated to systems of small number of particles and to small damping. In order to understand those results, we present an original analysis based on the decomposition of the particles motion in the normal modes of the chain. Our model explains all dynamic regimes observed in our simulations, and provides convincing estimates of the crossover times between those regimes.Comment: 30 pages, 9 figure

In situ spawning rate of the calanoid copepod Acartia clausi in a tropical lagoon (Ebrié, Côte d'Ivoire) : diel variations and effects of environmental factors

rate of the calanoid copepod Acartia clausi in a tropical lagoon (Ebrié, Côte d Ivoire): diel variations and effects of environmental factors. Zoological Studies 43(2): 244-254. Diel changes in the spawning rate of Acartia clausi were studied during several 24 h time series performed between 1993 and 1997 at several sites in Ebrié Lagoon (Côte d Ivoire) at which the morphology and hydrological structures differed. The daily egg production rate ranged from 8 to 60 eggs female-1 d-1 (5 % to 45 % of body carbon) and varied according to stations and periods. A correlation analysis, performed with the present results, revealed no significant effect of either envi-ronmental factors (salinity, temperature, and chlorophyll a biomass) or individual weight of females. However, the roles of salinity and food abundance (chlorophyll a) appeared when grouping the present data (1993-1997) with results from the same sites obtained previously (1981-1982) by Saint-Jean and Pagano (1984). This grouping showed the importance of inter-annual variations as compared to seasonal variations. The rhythm of egg laying was characterized by a night maximum which occurred earlier in the estuarine zone (22:00-01:00) than in the western oligohaline zone (04:00-06:00). These peaks of egg laying always occurred after the peak of gut fluorescence which was consistently observed at the beginning of the night (data from Kouassi et al

Configurational entropy of Wigner crystals

We present a theoretical study of classical Wigner crystals in two- and three-dimensional isotropic parabolic traps aiming at understanding and quantifying the configurational uncertainty due to the presence of multiple stable configurations. Strongly interacting systems of classical charged particles confined in traps are known to form regular structures. The number of distinct arrangements grows very rapidly with the number of particles, many of these arrangements have quite low occurrence probabilities and often the lowest-energy structure is not the most probable one. We perform numerical simulations on systems containing up to 100 particles interacting through Coulomb and Yukawa forces, and show that the total number of metastable configurations is not a well defined and representative quantity. Instead, we propose to rely on the configurational entropy as a robust and objective measure of uncertainty. The configurational entropy can be understood as the logarithm of the effective number of states; it is insensitive to the presence of overlooked low-probability states and can be reliably determined even within a limited time of a simulation or an experiment.Comment: 12 pages, 8 figures. This is an author-created, un-copyedited version of an article accepted for publication in J. Phys.: Condens. Matter. IOP Publishing Ltd is not responsible for any errors or omissions in this version of the manuscript or any version derived from it. The definitive publisher-authenticated version is available online at 10.1088/0953-8984/23/7/075302.

On the theory of the vortex state in the Fulde-Ferrell-Larkin-Ovchinnikov (FFLO) phase

We demonstrate that the vortex state in the Fulde-Ferrell-Larkin-Ovchinnikov (FFLO) phase may be very different depending on the field orientation relative to the crystalline axes. We calculate numerically the upper critical field near the tricritical point taking into account the modulation of the order parameter along the magnetic field as well as the higher Landau levels. For s-wave superconductors with the anisotropy described by an elliptical Fermi surface we propose a general scheme of the analysis of the angular dependence of upper critical field at all temperatures on the basis of the exact solution for the order parameter. Our results show that the transitions (with tilting magnetic field) between different types of mixed states may be a salient feature of the FFLO phase. Moreover we discuss the reasons for the first-order phase transition into the FFLO state in the case of CeCoIn5 compound.Comment: 7 figure

Transport properties of quantum dots in the Wigner molecule regime

The transport properties of quantum dots with up to N=7 electrons ranging from the weak to the strong interacting regime are investigated via the projected Hartree-Fock technique. As interactions increase radial order develops in the dot, with the formation of ring and centered-ring structures. Subsequently, angular correlations appear, signalling the formation of a Wigner molecule state. We show striking signatures of the emergence of Wigner molecules, detected in transport. In the linear regime, conductance is exponentially suppressed as the interaction strength grows. A further suppression is observed when centered-ring structures develop, or peculiar spin textures appear. In the nonlinear regime, the formation of molecular states may even lead to a conductance enhancement.Comment: 26 pages, 14 figures, Accepted for publication on New Journal of Physic

Feasibility of extended ultrasound examination of the fetal brain between 24 and 37 weeks’ gestation in low-risk pregnancies

Objectives: To assess the feasibility of identifying fetal brain structures and anatomic landmarks included in the anterior complex (AC) and posterior complex (PC), as well as the proximal hemisphere (PH). Methods: This was a prospective observational multicenter study of healthy pregnant women evaluated by ultrasound screening at 24 to 36 + 6 weeks' gestation. Six physicians performed transabdominal ultrasound, to obtain the planes required to visualize the AC, PC, and PH. Blind analysis by an expert and non-expert operator in fetal neurosonography was used to assess the structures included in each plane view. Results: In the population studied (n=366), structure detection rates for AC were over 95 %, with an agreement of 96 % when comparing expert and non-expert examiners. Visualization of the corpus callosum crossing the midline was detected in over 97 and 96 % of cases for the AC and PC, respectively, with an agreement of over 96 %. The PH plane, particularly through the posterior access via the mastoid fontanelle, enabled visualization of the proximal anatomical structures in almost 95 % of cases. Detection of the corpus callosum through the AC and PC, both proximal/distal germinal matrix (AC) and proximal Sylvian fissure through the anterior access (PH) in the 24-25 + 6, 26-31 + 6 and 32-36 + 6 weeks' gestation groups were successful in over 96 % of cases with high level of agreement. Conclusions: Inclusion of AC, PC, and PH later in pregnancy proves feasible with a high level of agreement between both expert and non-expert operators.info:eu-repo/semantics/publishedVersio

Le Rempart: Vol. 4: no 12 (1970: octobre)

https://scholar.uwindsor.ca/lerempartwindsor/1061/thumbnail.jp

Le Rempart: Vol. 2 no 7 (1968: mai)

https://scholar.uwindsor.ca/lerempartwindsor/1018/thumbnail.jp

Le Rempart: Vol. 1: no 12 (1967: octobre)

https://scholar.uwindsor.ca/lerempartwindsor/1011/thumbnail.jp