Molecular Shape Analysis based uponthe Morse-Smale Complexand the Connolly Function

Docking is the process by which two or several molecules form a complex. Docking involves the geometry of the molecular surfaces, as well as chemical and energetical considerations. In the mid-eighties, Connolly proposed a docking algorithm matching surface {\em knobs} with surface {\em depressions}. Knobs and depressions refer to the extrema of the {\em Connolly} function, which is defined as follows. Given a surface \calM bounding a three-dimensional domain $X$, and a sphere $S$ centered at a point $p$ of \calM, the Connolly function is equal to the solid angle of the portion of $S$ containing within $X$. We recast the notions of knob and depression of the Connolly function in the framework of Morse theory for functions defined over two-dimensional manifolds. First, we study the critical points of the Connolly function for smooth surfaces. Second, we provide an efficient algorithm for computing the Connolly function over a triangulated surface. Third, we introduce a Morse-Smale decomposition based on Forman's discrete Morse theory, and provide an $O(n\log n)$ algorithm to construct it. This decomposition induces a partition of the surface into regions of homogeneous flow, and provides an elegant way to relate local quantities to global ones ---from critical points to Euler's characteristic of the surface. Fourth, we apply this Morse-Smale decomposition to the discrete gradient vector field induced by Connolly's function, and present experimental results for several mesh models

BodyNet: Volumetric Inference of 3D Human Body Shapes

Human shape estimation is an important task for video editing, animation and fashion industry. Predicting 3D human body shape from natural images, however, is highly challenging due to factors such as variation in human bodies, clothing and viewpoint. Prior methods addressing this problem typically attempt to fit parametric body models with certain priors on pose and shape. In this work we argue for an alternative representation and propose BodyNet, a neural network for direct inference of volumetric body shape from a single image. BodyNet is an end-to-end trainable network that benefits from (i) a volumetric 3D loss, (ii) a multi-view re-projection loss, and (iii) intermediate supervision of 2D pose, 2D body part segmentation, and 3D pose. Each of them results in performance improvement as demonstrated by our experiments. To evaluate the method, we fit the SMPL model to our network output and show state-of-the-art results on the SURREAL and Unite the People datasets, outperforming recent approaches. Besides achieving state-of-the-art performance, our method also enables volumetric body-part segmentation.Comment: Appears in: European Conference on Computer Vision 2018 (ECCV 2018). 27 page

Theory of the anomalous Hall effect from the Kubo formula and the Dirac equation

A model to treat the anomalous Hall effect is developed. Based on the Kubo formalism and on the Dirac equation, this model allows the simultaneous calculation of the skew-scattering and side-jump contributions to the anomalous Hall conductivity. The continuity and the consistency with the weak-relativistic limit described by the Pauli Hamiltonian is shown. For both approaches, Dirac and Pauli, the Feynman diagrams, which lead to the skew-scattering and the side-jump contributions, are underlined. In order to illustrate this method, we apply it to a particular case: a ferromagnetic bulk compound in the limit of weak-scattering and free-electrons approximation. Explicit expressions for the anomalous Hall conductivity for both skew-scattering and side-jump mechanisms are obtained. Within this model, the recently predicted ''spin Hall effect'' appears naturally

Improving batch cooling seeded crystallization of an organic weed-killer using on-line ATR FTIR measurement of supersaturation

International audienceIn previous papers, a method for the calibration of ATR FTIR measurement of dissolved solid concentration during cooling crystallizations was presented, and efficient basic procedures for the determination of solubility and metastability curves were described. The present paper reports new experimental results. The crystallization of an organic product is studied thanks to on-line FTIR measurements of supersaturation and off-line crystal size distribution (CSD) determinations. The obtained information is shown to potentially allow a deeper examination of major industrial issues such as the reduction of batch-to-batch variations and the improvement of the CSD of the final particles. A particular attention is focused on the determination of appropriate seeding parameters such as the cooling rate of seeded slurries, the temperature of introduction and the amount of seed. The results obtained demonstrate that, although any modelling approach is outside the scope of this paper, the analysis of the measured supersaturation profiles allows some interpretation of mechanisms governing the final CSD, and consequently, the proposal of improved operating parameters

An Online Strategy To Increase the Average Crystal Size during Organic Batch Cooling Crystallization

International audienceIn situ attenuated total reflectance Fourier transform infrared (FTIR) measurements were shown to allow the online monitoring of supersaturation during solution crystallization processes, thus opening up new monitoring and control possibilities. With this aim in view, the monitoring of unseeded batch cooling solution crystallizations of two agrochemical products was investigated. The FTIR measurements of solute concentrations were used to develop a fines dissolution technique, based on a controlled heating-up procedure after primary nucleation. The strategy only requires the knowledge of the solubility curve and was deliberately designed to be robust and easy to implement. Two organic solute/solvent systems were studied. It is clearly demonstrated that the technique allows one to improve both the reproducibility of the final crystal size distribution and the mean crystal size. For Isoproturon, a well-known pesticide, the average final size is increased up to 90%. The efficiency of the monitoring procedure is also shown to depend on the solute/solvent system in question

On-line ATR FTIR measurement of supersaturation during solution crystallization processes. Calibration and applications on three solute/solvent systems

International audienceRecently, fourier transform infraRed (FTIR) spectroscopy was reported as a promising technique for in situ measurement of supersaturation during solution crystallization processes. The attenuated total reflection (ATR) probes appeared to be particularly suited to the chemical and physical complexity of industrial suspensions. However. to be used in an industrial contest, the technique must be easily and quickly adaptable to different systems. In order to achieve such an aim, a calibration procedure to monitor supersaturation from FTIR measurements is presented. General comments and recommendations about important technical aspects of the technique are also given. Then the technique is used to develop efficient procedures for the determination of solubility: and metastability curves. The crystallization of three line chemical products is studied, thanks to on-line FTIR measurements of supersaturation and off-line CSD determinations. It is shown that the monitoring of supersaturation is a valuable tool for an improved analysis of key phenomena involved during crystallization processes (primary and secondary nucleation. agglomeration, phase transition, seeding, etc.)