Weakly nonlocal irreversible thermodynamics - the Guyer-Krumhansl and the Cahn-Hilliard equations

Examples of irreversible thermodynamic theory of nonlocal phenomena are given, based on generalized entropy current. Thermodynamic currents and forces are identified to derive the Guyer-Krumhansl and Cahn-Hilliard equations. In the latter case Gurtin's rate dependent additional term is received through the thermodynamic approach.Comment: revise

A multi-level interface model for damaged masonry

The aim of the present work is to propose a new micro-mechanical model in the context of the deductive approach used to derive interface models. This model, based on a previous study introduced previously by A. Rekik and F. Lebon, is used to reproduce the damage in masonry by combining structural analysis and homogenization methods. The focal point of this method is to assume the existence of a third material, called interphase, which is a mixture of the two principal constituents of masonry, brick and mortar, and that is the interface between them. This new element presents a low thickness, a low stiffness and a given damage ratio. The mechanical problem of masonry, initially a 3D problem, is solved numerically as a 2D problem using finite element methods. The properties of the interface brick-mortar material are obtained using three essentials steps. First of all, an exact homogenisation of a laminates is used to define a first homogeneous equivalent medium named HEM-1. After, the assumption of damaged material is taken into account by using the general framework given by M. Kachanov to evaluate the global behaviour of the damaged HEM-1 defining thus a second equivalent homogeneous medium noted HEM-2. The last step consists in using an asymptotic analysis technique which is performed to model HEM-2 as an interface or a joint. The properties of this joint are deduced from those of the HEM-2 material as proposed in former papers. Particularly, through the second homogenization are taken into account the variability of microcracks oriented family and simultaneously the opening-closure effects (unilateral behaviour). Numerically this interface is modelled with connector finite elements. Numerical results are compared to experimental ones available in the literature

Tsallis statistics generalization of non-equilibrium work relations

We use third constraint formulation of Tsallis statistics and derive the $q$-statistics generalization of non-equilibrium work relations such as the Jarzynski equality and the Crooks fluctuation theorem which relate the free energy differences between two equilibrium states and the work distribution of the non-equilibrium processes.Comment: 5 page

Orbits and reversals of a drop rolling inside a horizontal circular hydraulic jump

We explore the complex dynamics of a non-coalescing drop of moderate size inside a circular hydraulic jump of the same liquid formed on a horizontal disk. In this situation the drop is moving along the jump and one observes two different motions: a periodic one (it orbitates at constant speed) and an irregular one involving reversals of the orbital motion. Modeling the drop as a rigid sphere exchanging friction with liquid across a thin film of air, we recover the orbital motion and the internal rotation of the drop. This internal rotation is experimentally observed.Comment: 5 pages, 6 figure

Convective instabilities in two superposed horizontal liquid layers heated laterally

This work is devoted to the theoretical study of the stability of two superposed horizontal liquid layers bounded by two solid planes and subjected to a horizontal temperature gradient. The liquids are supposed to be immiscible with a nondeformable interface. The forces acting on the system are buoyancy and interfacial tension. Four different flow patterns and temperature profiles are found for the basic state. A linear perturbative analysis with respect to two and three dimensional perturbations reveals the existence of three kind of patterns. Depending on the relative height of both liquids several situations are predicted: either wave propagation from cold to the hot regions, or waves propagating in the opposite direction or still stationary longitudinal rolls. The behavior of three different pairs of liquids which have been used in experiments on bilayers under vertical gradient by other authors have been examined. The instability mechanisms are discussed and a qualitative interpretation of the different behaviors exhibited by the system is provided. In some configurations it is possible to find a codimension-two point created by the interaction of two Hopf modes with different frequencies and wavenumbers. These results suggest to consider two liquid layers as an interesting prototype for the study of propagation and interaction of waves in the context of the B\'enard-Marangoni problem.Comment: 21 pages, 9 figures, 2 tables;accepted to be published in PR

Bacterial Colonisation of the Nasal and Nasopharyngeal Cavities in Children: The Generation R Study

Humans are surrounded by microorganisms: viruses, bacteria, fungi and parasites. We can divide these organisms into the following four categories: innocent, beneficial, harmful and dangerous. Most of the times, microorganisms are not harmful and are therefore referred to as non-pathogenic. Innocent microorganisms cause no harm nor do they provide benefits. Benefi cial microorganisms even provide a significant advantage for humans by aiding digestion or preventing pathogenic microorganisms to cause infection via colonisation resistance. By colonising the respiratory and/or gastro-intestinal tract, these organisms prevent pathogenic microorganisms to settle and cause harm. Pathogens causing harm in certain cases, but not per definition, are grouped into the harmful category. However, microbes that fall into the dangerous category comprise organisms that cause morbidity and mortality in humans even in those with an intact immune system

Modelling plant-insect interactions: theory and application in crop protection

Reducing the use of chemicals and thus developing environmentally friendlier methods such as biological control is one of the current important challenges in crop protection. But, even if biological control has developed very rapidly in the past decades, its successes in efficiently controlling insect pests have been mixed. Modelling and simulation tools can help to grasp biological interactions and also improve biological control. At the core of any biological control program lies a tri-trophic food chain linking plants, pests and their natural enemies. However, up to now, biological control modelling has primarily focused on pests-natural enemies interactions considering somehow that crop yield is not affected by the pests. In practice this assumption is not always realistic. If the main objective of the control is to maintain the crop yield above a critical threshold, then plant growth and plant-insect interactions have to be taken into account...Not an easy task! Using a minimal modelling approach, our contribution focuses on plant-insect interactions as a first step towards a full plants-pests-natural enemies model. Plant growth is modelled in such a way that the growth pattern of the plant and its final biomass are both dependent on the initial pest's infestation level. This contrasts with most population dynamics models, including plant-grazers models, which after some transients tend to produce similar dynamics for different initial conditions. Numerical simulations are provided using parameters identified in the literature to illustrate the model dynamics on the interaction between tomato plants and a leafminer, Tuta absoluta. In particular, the results show that well timed pests control interventions (mechanical control or non-persistent bio-pesticides) have important effects on the growth pattern and the final biomass of the tomato plants. (Résumé d'auteur

Hare and moral thinking

This thesis is a critical study of R.M. Hare's recent work "Moral Thinking" and an attempt to develop some of the ideas in it. Hare's book contains illuminating discussions on many ethical and metaethical issues, but two central themes can be isolated. One is his suggestion that there are two levels of moral thinking, the critical and the intuitive; the other is his detailed argument that preference-utilitarianism operates at the most fundamental level of moral thinking, the critical level, to ultimately determine what we ought to do.Hare's argument for utilitarianism will be studied in depth. In particular his appeal to linguistic intuitions, his assertion that 'ought' is prescriptive and the argument of chapters 5 - 6 of "Moral Thinking" will all be assessed, as will his claim that prudence rules out amoralism.Hare admits that his book leaves some important issues less than fully discussed: I attempt to see what implications these have for Hare'stheory. Most of these relate to the concept of 'preference'; in particular to the question of whether 'irrational' preference should be excluded.I also try to see what connection there is between Hare's preference-utilitarianism and happiness based theories. These issues are of independent interest as they affect the feasibility of preference-utilitarianism in general, not just Hare's version of it. Finally, Hare's suggestion that there are two levels of moral thinking will be assessed, as well as his proposal that this allows both for a defence of utilitarianism and a reconciliation between it and deontological theories.<p

Human adenosine A2A receptor : molecular mechanism of ligand binding and activation

Adenosine receptors (ARs) comprise the P1 class of purinergic receptors and belong to the largest family of integral membrane proteins in the human genome, the G protein-coupled receptors (GPCRs). ARs are classified into four subtypes, A1, A2A, A2B, and A3, which are all activated by extracellular adenosine, and play central roles in a broad range of physiological processes, including sleep regulation, angiogenesis and modulation of the immune system. ARs are potential therapeutic targets in a variety of pathophysiological conditions, including sleep disorders, cancer, and dementia, which has made them important targets for structural biology. Over a decade of research and innovation has culminated with the publication of more than 30 crystal structures of the human adenosine A2A receptor (A2AR), making it one of the best structurally characterized GPCRs at the atomic level. In this review we analyze the structural data reported for A2AR that described for the first time the binding of mode of antagonists, including newly developed drug candidates, synthetic and endogenous agonists, sodium ions and an engineered G protein. These structures have revealed the key conformational changes induced upon agonist and G protein binding that are central to signal transduction by A2AR, and have highlighted both similarities and differences in the activation mechanism of this receptor compared to other class A GPCRs. Finally, comparison of A2AR with the recently solved structures of A1R has provided the first structural insight into the molecular determinants of ligand binding specificity in different AR subtypes