Wundt's laboratory at Leipzig in 1891.

This article describes W. Wundt's laboratory at Leipzig in 1891 as viewed by a Belgian psychologist, J. J. Van Biervliet (1859-1945). Although few French-speaking psychologists worked in Wundt's laboratory, several of those who did reports wrote on how students were trained there. Van Biervliet decided to visit Wundt's laboratory at Leipzig in order to strengthen the foundation of his own laboratory at the University of Ghent and to become familiar with Wundt's experimental techniques. A translation of J. J. Van Biervliet's (1892) article "Experimental Psychology. Wundt's Institute at Leipzig" is presented here as one of the first and most complete articles in French describing the functioning of Wundt's laboratory. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Early Experience and Postembryonic Maturation of Body Patterns in Cuttlefish (Sepia officinalis).

This study investigates effects of the environment on the maturation of body patterns in cuttlefish (Sepia officinalis). Cuttlefish were reared either individually on a uniform background, which the authors have termed uniform-solitary conditions (Group A), or grouped on variegated backgrounds, which the authors have termed varied-social conditions (Group B). At Days 1, 15, 30, and 60, juveniles were placed individually in perceptually different testing conditions, either on small, variegated stones or on a uniform pale gray background. During development in both testing conditions, juveniles from Group B concealed themselves differently from those from Group A. Thus, it appears that the response to the background is subject to individual experience. Some hypotheses are discussed relating to the effect of early experience on the maturation of body patterns. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Elastically driven morphology of coherent trigonal precipitates inside a close-packed hexagonal matrix

The influence of a crystallographic symmetry break on the morphology of precipitates during the coherent precipitation of a trigonal phase in a close-packed hexagonal matrix is analyzed. It is pointed out that in spite of the isotropy of the stress-free strain of the precipitate in the basal plane, the existence of an extra elastic constant in the precipitate (associated to the loss of symmetry) induces a morphological evolution from a shape having a symmetry of revolution around the threefold axis to a needle-like one oriented along the compact directions in the basal plane. These general considerations are applied to the case of zirconium hydrides, the crystallography of which has recently been identified to be coherent with that of the αZr matrix.     

Variable‐Wavelength Quick Scanning Nanofocused X‐Ray Microscopy for In Situ Strain and Tilt Mapping

Compression of micropillars is followed in situ by a quick nanofocused X‐ray scanning microscopy technique combined with 3D reciprocal space mapping. Compared to other attempts using X‐ray nanobeams, it avoids any motion or vibration that would lead to a destruction of the sample. The technique consists of scanning both the energy of the incident nanofocused X‐ray beam and the in‐plane translations of the focusing optics along the X‐ray beam. Here, the approach by imaging the strain and lattice orientation of Si micropillars and their pedestals during in situ compression is demonstrated. Varying the energy of the incident beam instead of rocking the sample and mapping the focusing optics instead of moving the sample supplies a vibration‐free measurement of the reciprocal space maps without removal of the mechanical load. The maps of strain and lattice orientation are in good agreement with the ones recorded by ordinary rocking‐curve scans. Variable‐wavelength quick scanning X‐ray microscopy opens the route for in situ strain and tilt mapping toward more diverse and complex materials environments, especially where sample manipulation is difficult.     

A virtual test facility for the efficient simulation of solid material response under strong shock and detonation wave loading

A virtual test facility (VTF) for studying the three-dimensional dynamic response of solid materials subject to strong shock and detonation waves has been constructed as part of the research program of the Center for Simulating the Dynamic Response of Materials at the California Institute of Technology. The compressible fluid flow is simulated with a Cartesian finite volume method and treating the solid as an embedded moving body, while a Lagrangian finite element scheme is employed to describe the structural response to the hydrodynamic pressure loading. A temporal splitting method is applied to update the position and velocity of the boundary between time steps. The boundary is represented implicitly in the fluid solver with a level set function that is constructed on-the-fly from the unstructured solid surface mesh. Block-structured mesh adaptation with time step refinement in the fluid allows for the efficient consideration of disparate fluid and solid time scales. We detail the design of the employed object-oriented mesh refinement framework AMROC and outline its effective extension for fluid–structure interaction problems. Further, we describe the parallelization of the most important algorithmic components for distributed memory machines and discuss the applied partitioning strategies. As computational examples for typical VTF applications, we present the dynamic deformation of a tantalum cylinder due to the detonation of an interior solid explosive and the impact of an explosion-induced shock wave on a multi-material soft tissue body.     

Structured prediction with reinforcement learning

We formalize the problem of Structured Prediction as a Reinforcement Learning task. We first define a Structured Prediction Markov Decision Process (SP-MDP), an instantiation of Markov Decision Processes for Structured Prediction and show that learning an optimal policy for this SP-MDP is equivalent to minimizing the empirical loss. This link between the supervised learning formulation of structured prediction and reinforcement learning (RL) allows us to use approximate RL methods for learning the policy. The proposed model makes weak assumptions both on the nature of the Structured Prediction problem and on the supervision process. It does not make any assumption on the decomposition of loss functions, on data encoding, or on the availability of optimal policies for training. It then allows us to cope with a large range of structured prediction problems. Besides, it scales well and can be used for solving both complex and large-scale real-world problems. We describe two series of experiments. The first one provides an analysis of RL on classical sequence prediction benchmarks and compares our approach with state-of-the-art SP algorithms. The second one introduces a tree transformation problem where most previous models fail. This is a complex instance of the general labeled tree mapping problem. We show that RL exploration is effective and leads to successful results on this challenging task. This is a clear confirmation that RL could be used for large size and complex structured prediction problems.     

Photopolymerization of Pollen Based Biosourced Composites and Applications in 3D and 4D Printing

Pollen have the potential to be effective plant-based biorenewable reinforcing fillers for polymers due to their chemical stability and unique micro- or nano-structured surfaces. Pollen-polymer composites can form the basis for a new class of light-weight and sustainable materials if compatible polymer-filler systems can be engineered through photopolymerization, but this idea is previously unexplored. The first demonstration of photopolymerization and 3D printing with the incorporation of pine pollen as filler in poly(ethylene glycol) diacrylate are presented. The filler properties affecting the related depth of cure and the mechanical, thermal, and functional properties are examined in detail. In addition, the lithography technique is applied to the photocomposites for the production of 3D patterns. 4D printing behavior is also possible through the water swelling and dehydration induced actuation of the 3D printed composites with spatial resolution features. This work is expected to provide a new way to a field for photopolymerization reactions in natural material-resin composites and thereby to expand potential applications in 3D and 4D printing.