Unifying approach for fluctuation theorems from joint probability distributions

Any decomposition of the total trajectory entropy production for Markovian systems has a joint probability distribution satisfying a generalized detailed fluctuation theorem, when all the contributing terms are odd with respect to time reversal. The expression of the result does not bring into play dual probability distributions, hence easing potential applications. We show that several fluctuation theorems for perturbed non-equilibrium steady states are unified and arise as particular cases of this general result. In particular, we show that the joint probability distribution of the system and reservoir trajectory entropies satisfy a detailed fluctuation theorem valid for all times although each contribution does not do it separately

3-D chemistry-transport model Polair: numerical issues, validation and automatic-differentiation strategy

International audienceWe briefly present in this short paper some issues related to the development and the validation of the three-dimensional chemistry-transport model Polair. Numerical studies have been performed in order to let Polair be an efficient and robust solver. This paper summarizes and comments choices that were made in this respect. Simulations of relevant photochemical episodes were led to assess the validity of the model. The results can be considered as a validation, which allows next studies to focus on fine modeling issues. A major feature of Polair is the availability of a tangent linear mode and an adjoint mode entirely generated by automatic differentiation. Tangent linear and adjoint modes grant the opportunity to perform detailed sensitivity analyses and data assimilation. This paper shows how inverse modeling is achieved with Polair

Polyphemus : une plate-forme multimodèles pour la pollution atmosphérique et l'évaluation des risques

National audienceCet article présente le système de modélisation de la qualité de l'air Polyphemus, ses principales fonctionnalités et quelques applications. Polyphemus est dédié à la modélisation de la dispersion atmosphérique de traceurs passifs ou d'espèces réactives aux échelles locale, régionale et continentale. Polyphemus est développé au CEREA, laboratoire commun entre EDF R&D et lʼÉcole des Ponts et au sein dʼun projet commun avec lʼInstitut national de recherche en informatique et automatique (INRIA), avec le soutien de lʼIRSN et de lʼINERIS. Polyphemus est un système dʼun type nouveau qui se distingue de lʼapproche classique du " modèle tout en un " par sa construction modulaire, notamment fondée sur des bibliothèques et des pilotes manipulant les modèles de dispersion. Accueillant plusieurs modèles, Polyphemus est une plate-forme et non un modèle. Une de ses fonctionnalités notables est sa capacité à effectuer des simulations multimodèles, ce qui permet d'évaluer des incertitudes. Plusieurs méthodes dʼassimilation de données font aussi partie du système afin de pouvoir intégrer des données fournies par des réseaux de mesure

Structure-based stabilization of insulin as a therapeutic protein assembly via enhanced aromatic-aromatic interactions

Key contributions to protein structure and stability are provided by weakly polar interactions, which arise from asymmetric electronic distributions within amino acids and peptide bonds. Of particular interest are aromatic side chains whose directional π-systems commonly stabilize protein interiors and interfaces. Here, we consider aromatic-aromatic interactions within a model protein assembly: the dimer interface of insulin. Semi-classical simulations of aromatic-aromatic interactions at this interface suggested that substitution of residue TyrB26 by Trp would preserve native structure while enhancing dimerization (and hence hexamer stability). The crystal structure of a [TrpB26]insulin analog (determined as a T3Rf3 zinc hexamer at a resolution of 2.25 Å) was observed to be essentially identical to that of WT insulin. Remarkably and yet in general accordance with theoretical expectations, spectroscopic studies demonstrated a 150-fold increase in the in vitro lifetime of the variant hexamer, a critical pharmacokinetic parameter influencing design of long-acting formulations. Functional studies in diabetic rats indeed revealed prolonged action following subcutaneous injection. The potency of the TrpB26-modified analog was equal to or greater than an unmodified control. Thus, exploiting a general quantum-chemical feature of protein structure and stability, our results exemplify a mechanism-based approach to the optimization of a therapeutic protein assembly

Joint probability distributions and fluctuation theorems

We derive various exact results for Markovian systems that spontaneously relax to a non-equilibrium steady-state by using joint probability distributions symmetries of different entropy production decompositions. The analytical approach is applied to diverse problems such as the description of the fluctuations induced by experimental errors, for unveiling symmetries of correlation functions appearing in fluctuation-dissipation relations recently generalised to non-equilibrium steady-states, and also for mapping averages between different trajectory-based dynamical ensembles. Many known fluctuation theorems arise as special instances of our approach, for particular two-fold decompositions of the total entropy production. As a complement, we also briefly review and synthesise the variety of fluctuation theorems applying to stochastic dynamics of both, continuous systems described by a Langevin dynamics and discrete systems obeying a Markov dynamics, emphasising how these results emerge from distinct symmetries of the dynamical entropy of the trajectory followed by the system For Langevin dynamics, we embed the "dual dynamics" with a physical meaning, and for Markov systems we show how the fluctuation theorems translate into symmetries of modified evolution operators.Comment: 39 pages, 1 figure. Minor revision, as suggested by referees. A couple of references and equations added. Acknowledgements slightly modifie

Pengaruh Penyuluhan Kesehatan Terhadap Pengetahuan Masyarakat Tentang Pemanfaatan Jeruk Nipis Sebagai Tanaman Obat Di Desa Huwongo Kabupaten Boalemo

Tanaman jeruk nipis merupakan salah satu jenis tanaman obat. Namun pemanfaatan jeruk nipis di kalangan masyarakat di desa huwongo masih kurang. maka sangat penting untuk memberikan pengaruh penyuluhan kesehatan terhadap pengetahun masyarakat tentang pemanfaatan jeruk nipis sebagai tanaman obat. Metode penelitian yang digunakan adalah dengan rancangan penelitian quasi eksperimental dengan pendekatan one group pra-post test design. Populasi penelitian berjumlah 373 kepala keluarga. Sampel dalam penelitian ini sebanyak 80 responden dengan teknik pengambilan sampel Simple random sampling. Hasil penelitian didapatkan bahwa sebelum diberikan penyuluhan kesehatan terdapat 67,8% yang berpengetahuan cukup hal ini dikarenakan banyak masyarakat belum memahami manfaat jeruk nipis. Setelah diberikan penyuluhan kesehatan terdapat berpengetahuan baik 97,5% hal ini dapat dikatakan bahwa penyuluhan kesehatan memberikan konstribusi yang baik dalam peningkatan pengetahuan masyarakat dalam pemanfaatan jeruk nipis. Hasil dari uji wilcoxon menunjukkan bahwa terdapat pengaruh pengetahuan sebelum dan setelah diberikan penyuluhan kesehatan dengan nilai p = 0,00

Hysteretic depinning of a particle in a periodic potential: Phase diagram and criticality

We consider a massive particle driven with a constant force in a periodic potential and subjected to a dissipative friction. As a function of the drive and damping, the phase diagram of this paradigmatic model is well known to present a pinned, a sliding, and a bistable regime separated by three distinct bifurcation lines. In physical terms, the average velocity $v$ of the particle is nonzero only if either (i) the driving force is large enough to remove any stable point, forcing the particle to slide, or (ii) there are local minima but the damping is small enough, below a critical damping, for the inertia to allow the particle to cross barriers and follow a limit cycle; this regime is bistable and whether $v > 0$ or $v = 0$ depends on the initial state. In this paper, we focus on the asymptotes of the critical line separating the bistable and the pinned regimes. First, we study its behavior near the "triple point" where the pinned, the bistable, and the sliding dynamical regimes meet. Just below the critical damping we uncover a critical regime, where the line approaches the triple point following a power-law behavior. We show that its exponent is controlled by the normal form of the tilted potential close to its critical force. Second, in the opposite regime of very low damping, we revisit existing results by providing a simple method to determine analytically the exact behavior of the line in the case of a generic potential. The analytical estimates, accurately confirmed numerically, are obtained by exploiting exact soliton solutions describing the orbit in a modified tilted potential which can be mapped to the original tilted washboard potential. Our methods and results are particularly useful for an accurate description of underdamped nonuniform oscillators driven near their triple point.Comment: 13 pages, 13 figures, published versio

Autoignition of R32 and R410 Refrigerant Mixtures with Lubricating Oil

Refrigerant R32 (difluoromethane, formula CH2F2) is a working fluid with favorable environmental and performance properties. However, it can be slightly flammable under certain conditions (13 – 30% by volume in air), with a flammability classification of 2L. The risks of ignition, fire, and hazardous decomposition products are being assessed in our laboratories using experiments, risk analysis, and computational fluid dynamics simulations. R32 has entered service in Japan and is being considered for service in the US. Its adoption is being hindered by its slight flammability in air. Past research has examined the flammability of pure refrigerants without considering the effects of the presence of lubricating oil. The concentration of oil released in a refrigerant leak can vary depending on the location of the leak and the operating state of the equipment. In this study, mixtures of R32 and R410 with lubricating oil are impinged onto a hot horizontal metal surface to examine autoignition behavior. The tests simulate a leak in a cooling system that impinges on a heating element. The hypothesis of this research is that the autoignition behavior of these mixtures is dominated by the presence of lubricating oil, not by differences in the refrigerant flammability. Only preliminary results are available at the time of abstract preparation, but extensive results will be included in the presentation at Purdue