Equilibrium of a Brownian particle with coordinate dependent diffusivity and damping: Generalized Boltzmann distribution

Fick's law for coordinate dependent diffusivity is derived. Corresponding diffusion current in the presence of coordinate dependent diffusivity is consistent with the form as given by Kramers-Moyal expansion. We have obtained the equilibrium solution of the corresponding Smoluchowski equation. The equilibrium distribution is a generalization of the Boltzmann distribution. This generalized Boltzmann distribution involves an effective potential which is a function of coordinate dependent diffusivity. We discuss various implications of the existence of this generalized Boltzmann distribution for equilibrium of systems with coordinate dependent diffusivity and damping.Comment: 11 pages, 1 figur

Creep motion of a granular pile induced by thermal cycling

We report a time-resolved study of the dynamics associated with the slow compaction of a granular column submitted to thermal cycles. The column height displays a complex behavior: for a large amplitude of the temperature cycles, the granular column settles continuously, experiencing a small settling at each cycle; By contrast, for small-enough amplitude, the column exhibits a discontinuous and intermittent activity: successive collapses are separated by quiescent periods whose duration is exponentially distributed. We then discuss potential mechanisms which would account for both the compaction and the transition at finite amplitude.Comment: 4 pages, 5 figures, accepted for publication in Physical Review Letters (05sep08

Discovery and Presentation of Evidence in Adversary and Nonadversary Proceedings

In order to evaluate fully the advantage claimed for the adversary model we sought to add a third element that would test the hypothesis under a variety of conditions. The degree to which the evidence discovered in a case favors one party at the expense of another appeared to meet this criterion. This fact-distribution element is a pervasive condition of legal conflict resolution that, intuition suggests, may significantly influence information search and transmission. Further, this variable could be easily and accurately controlled by regulating the flow of favorable information acquired by the subjects during the experiment. The remainder of this article reports a laboratory experiment intended to cast light on both the specific claim made on behalf of the adversary system and the nature of information processing in legal systems generally

Recouvrance hygrothermique du bois vert. I. Influence de la température. Cas du jujubier (Ziziphus lotus (L) Lam)

Le chauffage du bois vert met en jeu une compétition entre plusieurs mécanismes de déformation. A la déformation thermique proprement dite, réversible et caractérisée par un coefficient d'expansion négatif en dessous de la température de transition vitreuse de la lignine, se superpose lors du premier chauffage la recouvrance viscoélastique de déformations bloquées lors de l'élaboration sous contrainte du bois dans l'arbre. Il en résulte une dilatation tangentielle, associée à une contraction radiale plus faible, à l'origine des fentes à coeur induites par l'étuvage humide des grumes. La séparation des mécanismes de déformation associés à la "recouvrance hygrothermique" a été tentée pour le jujubier (Ziziphus lotus (L) Lam) à partir de mesures silmutanées, pour plusieurs modes de chargement en température, des déformations tangentielle et radiale, permettant notamment d'interpréter une décroissance transitoire de la déformation tangentielle observée lors du premier chauffage. (Résumé d'auteur

Quantum phase transition of dynamical resistance in a mesoscopic capacitor

We study theoretically dynamic response of a mesoscopic capacitor, which consists of a quantum dot connected to an electron reservoir via a point contact and capacitively coupled to a gate voltage. A quantum Hall edge state with a filling factor nu is realized in a strong magnetic field applied perpendicular to the two-dimensional electron gas. We discuss a noise-driven quantum phase transition of the transport property of the edge state by taking into account an ohmic bath connected to the gate voltage. Without the noise, the charge relaxation for nu>1/2 is universally quantized at R_q=h/(2e^2), while for nu<1/2, the system undergoes the Kosterlitz-Thouless transtion, which drastically changes the nature of the dynamical resistance. The phase transition is facilitated by the noisy gate voltage, and we see that it can occur even for an integer quantum Hall edge at nu=1. When the dissipation by the noise is sufficiently small, the quantized value of R_q is shifted by the bath impedance.Comment: 5 pages, 2 figures, proceeding of the 19th International Conference on the Application of High Magnetic Fields in Semiconductor Physics and Nanotechnology (HMF-19

Who uses running apps and sports watches? : determinants and consumer profiles of event runners' usage of running-related smartphone applications and sports watches.

Individual and unorganized sports with a health-related focus, such as recreational running, have grown extensively in the last decade. Consistent with this development, there has been an exponential increase in the availability and use of electronic monitoring devices such as smartphone applications (apps) and sports watches. These electronic devices could provide support and monitoring for unorganized runners, who have no access to professional trainers and coaches. The purpose of this paper is to gain insight into the characteristics of event runners who use running-related apps and sports watches. This knowledge is useful from research, design, and marketing perspectives to adequately address unorganized runners' needs, and to support them in healthy and sustainable running through personalized technology. Data used in this study are drawn from the standardized online Eindhoven Running Survey 2014 (ERS14). In total, 2,172 participants in the Half Marathon Eindhoven 2014 completed the questionnaire (a response rate of 40.0%). Binary logistic regressions were used to analyze the impact of socio-demographic variables, running- related variables, and psychographic characteristics on the use of running-related apps and sports watches. Next, consumer profiles were identified. The results indicate that the use of monitoring devices is affected by socio-demographics as well as sports-related and psychographic variables, and this relationship depends on the type of monitoring device. Therefore, distinctive consumer profiles have been developed to provide a tool for designers and manufacturers of electronic running-related devices to better target (unorganized) runners' needs through personalized and differentiated approaches. Apps are more likely to be used by younger, less experienced and involved runners. Hence, apps have the potential to target this group of novice, less trained, and unorganized runners. In contrast, sports watches are more likely to be used by a different group of runners, older and more experienced runners with higher involvement. Although apps and sports watches may potentially promote and stimulate sports participation, these electronic devices do require a more differentiated approach to target specific needs of runners. Considerable efforts in terms of personalization and tailoring have to be made to develop the full potential of these electronic devices as drivers for healthy and sustainable sports participation.</p

Quantum Coherence at Low Temperatures in Mesoscopic Systems: Effect of Disorder

We study the disorder dependence of the phase coherence time of quasi one-dimensional wires and two-dimensional (2D) Hall bars fabricated from a high mobility GaAs/AlGaAs heterostructure. Using an original ion implantation technique, we can tune the intrinsic disorder felt by the 2D electron gas and continuously vary the system from the semi-ballistic regime to the localized one. In the diffusive regime, the phase coherence time follows a power law as a function of diffusion coefficient as expected in the Fermi liquid theory, without any sign of low temperature saturation. Surprisingly, in the semi-ballistic regime, it becomes independent of the diffusion coefficient. In the strongly localized regime we find a diverging phase coherence time with decreasing temperature, however, with a smaller exponent compared to the weakly localized regime.Comment: 21 pages, 30 figure

Swimming, Feeding and Inversion of Multicellular Choanoflagellate Sheets

The recent discovery of the striking sheet-like multicellular choanoflagellate species $Choanoeca~flexa$ that dynamically interconverts between two hemispherical forms of opposite orientation raises fundamental questions in cell and evolutionary biology, as choanoflagellates are the closest living relatives of animals. It similarly motivates questions in fluid and solid mechanics concerning the differential swimming speeds in the two states and the mechanism of curvature inversion triggered by changes in the geometry of microvilli emanating from each cell. Here we develop fluid dynamical and mechanical models to address these observations and show that they capture the main features of the swimming, feeding, and inversion of $C.~flexa$ colonies.Comment: 5 pages, 3 figures + Supplementary Material (videos on request from REG

Inequality and Procedural Justice in Social Dilemmas

This study investigates the influence of resource inequality and the fairness of the allocation procedure of unequal resources on cooperative behavior in social dilemmas. We propose a simple formal behavioral model that incorporates conflicting selfish and social motivations. This model allows us to predict how inequality influences cooperative behavior. Allocation of resources is manipulated by three treatments that vary in terms of procedural justice: allocating resources randomly, based on merit, and based on ascription. As predicted, procedural justice influences cooperation significantly. Moreover, gender is found to be an important factor interacting with the association between procedural justice and cooperative behavior.