Blockwise SVD with error in the operator and application to blind deconvolution

We consider linear inverse problems in a nonparametric statistical framework. Both the signal and the operator are unknown and subject to error measurements. We establish minimax rates of convergence under squared error loss when the operator admits a blockwise singular value decomposition (blockwise SVD) and the smoothness of the signal is measured in a Sobolev sense. We construct a nonlinear procedure adapting simultaneously to the unknown smoothness of both the signal and the operator and achieving the optimal rate of convergence to within logarithmic terms. When the noise level in the operator is dominant, by taking full advantage of the blockwise SVD property, we demonstrate that the block SVD procedure overperforms classical methods based on Galerkin projection or nonlinear wavelet thresholding. We subsequently apply our abstract framework to the specific case of blind deconvolution on the torus and on the sphere

Gender homophily from spatial behavior in a primary school: a sociometric study

We investigate gender homophily in the spatial proximity of children (6 to 12 years old) in a French primary school, using time-resolved data on face-to-face proximity recorded by means of wearable sensors. For strong ties, i.e., for pairs of children who interact more than a defined threshold, we find statistical evidence of gender preference that increases with grade. For weak ties, conversely, gender homophily is negatively correlated with grade for girls, and positively correlated with grade for boys. This different evolution with grade of weak and strong ties exposes a contrasted picture of gender homophily

Regimes of waste (im)perceptibility in the life cycle of metal

The transnational legal landscape governing waste management, recycling, and disposal remains narrowly focused on the economic possibilities of ‘end-of-life products', while paying little to no consideration to the much greater quantities of waste generated at the beginning of the product's lifecycle. We explore the existing regulatory framework through the duality of (in)visibility: whereas the circular economy of recycling increasingly integrates synthetic waste into the visible, the extractive industry buries biophysical waste into a ‘cradle-to-grave' economy. We argue that waste becomes a perceptible matter of concern when commodified into a new cycle of wealth accumulation. By contrast, when waste is abandoned on mining sites, it becomes an imperceptible matter of fact. Mining risks, although perceptible to the industry and affected communities, are rendered less visible to the administrative bodies in charge of regulating them. Therefore, waste (im)perceptibility is industrially manufactured according to the commercial aspects of a product, rather than its toxicity

Utilisation and evaluation of cooperative case-based teaching for integration of microbiology and pharmacology in veterinary education

Purpose: Integrating basic sciences with clinical disciplines while fostering clinical reasoning capabilities is difficult. We investigated the utilisation of diagnostic specimens and, a cooperative, case-based learning and teaching model to integrate principles of antimicrobial drug pharmacology and microbiology in the fifth year of a veterinary course. Methods: In small groups, students were assigned diagnostic specimens from which they isolated and identified clinically relevant microorganisms and then performed antimicrobial susceptibility tests based on a review of pharmacology, microbiology and pathophysiology. Results were recorded and analysed followed by a student-led integrative tutorial. Learning outcomes were assessed via individually written reports discussing the disease process, interpretation of diagnostic results and, recommendations and rationales for therapeutic interventions. Results: This approach yielded high quality student reports that conformed to antimicrobial prescription guidelines with consistently high summative assessment scores. Mean scores for the final report in this learning activity were: 82 ± 12%, 80 ± 12% and 80 ± 11% for 2015, 2016 and 2017 cohorts respectively; over the same time period, 98 ± 1% of students indicated that these learning activities facilitated the development of confidence, professional knowledge and skills. Discussion: This was a consistent approach for integrating principles of veterinary pharmacology and microbiology in clinical disciplines. These data illustrate the benefit of a systematic application of a cooperative, case-based learning and teaching model in integrating pre-clinical and clinical disciplines in a bachelor of veterinary science course

Inverse condensation of adsorbed molecules with two conformations

Conventional gas-liquid phase transitions feature a coexistence line that has a monotonic and positive slope in line with our intuition that cooling always leads to condensation. Here we study the inverse phenomenon, condensation of adsorbed organic molecules into dense domains upon heating. Our considerations are motivated by recent experiments [Aeschlimann et al., Angew. Chem. (2021)], which demonstrate the partial dissolution of an ordered molecular monolayer and the mobilization of molecules upon cooling. We introduce a simple lattice model in which each site can have three states corresponding to unoccupied and two discernible molecular conformations. We investigate this model through Monte Carlo simulations, mean-field theory, and exact results based on the analytical solution of the Ising model in two dimensions. Our results should be broadly applicable to molecules with distinct conformations that have sufficiently different entropies or heat capacities

An elasto-visco-plastic model for immortal foams or emulsions

A variety of complex fluids consist in soft, round objects (foams, emulsions, assemblies of copolymer micelles or of multilamellar vesicles -- also known as onions). Their dense packing induces a slight deviation from their prefered circular or spherical shape. As a frustrated assembly of interacting bodies, such a material evolves from one conformation to another through a succession of discrete, topological events driven by finite external forces. As a result, the material exhibits a finite yield threshold. The individual objects usually evolve spontaneously (colloidal diffusion, object coalescence, molecular diffusion), and the material properties under low or vanishing stress may alter with time, a phenomenon known as aging. We neglect such effects to address the simpler behaviour of (uncommon) immortal fluids: we construct a minimal, fully tensorial, rheological model, equivalent to the (scalar) Bingham model. Importantly, the model consistently describes the ability of such soft materials to deform substantially in the elastic regime (be it compressible or not) before they undergo (incompressible) plastic creep -- or viscous flow under even higher stresses.Comment: 69 pages, 29 figure

The Bismut-Elworthy-Li type formulae for stochastic differential equations with jumps

Consider jump-type stochastic differential equations with the drift, diffusion and jump terms. Logarithmic derivatives of densities for the solution process are studied, and the Bismut-Elworthy-Li type formulae can be obtained under the uniformly elliptic condition on the coefficients of the diffusion and jump terms. Our approach is based upon the Kolmogorov backward equation by making full use of the Markovian property of the process.Comment: 29 pages, to appear in Journal of Theoretical Probabilit