Éditorial: Enfin,une voix canadienne!

Abstract

This article investigates some of the specific features involved in accommodating the idea of actual infinity as it appears in set theory. It focuses on the conceptions of two individuals with sophisticated mathematics background, as manifested in their engagement with variations of a well-known paradox: the ping-pong ball conundrum. The APOS theory is used as a framework to interpret participants’ efforts to resolve the paradoxes. The cases discussed focus on how transfinite subtraction may be conceptualized, and they suggest that there is more to accommodating the idea of actual infinity than the ability to act on a completed object—rather, it is the manner in which objects are acted upon that is also significant.     

The PKR/P38/RIPK1 Signaling Pathway as a Therapeutic Target in Alzheimer’s Disease

Neuropathological lesions in Alzheimer’s disease (AD) include amyloid plaques formed by the accumulation of amyloid peptides, neurofibrillary tangles made of hyperphosphorylated tau protein, synaptic and neuronal degenerations, and neuroinflammation. The cause of AD is unknown, but according to the amyloid hypothesis, amyloid oligomers could lead to the activation of kinases such as eukaryotic translation initiation factor 2-alpha kinase 2 (PKR), p38, and receptor-interacting serine/threonine-protein kinase 1 (RIPK1), which all belong to the same stress-activated pathway. Many toxic kinase activations have been described in AD patients and in experimental models. A p38 mitogen-activated protein kinase inhibitor was recently tested in clinical trials but with unsuccessful results. The complex PKR/P38/RIPK1 (PKR/dual specificity mitogen-activated protein kinase kinase 6 (MKK6)/P38/MAP kinase-activated protein kinase 2 (MK2)/RIPK1) is highly activated in AD brains and in the brains of AD transgenic animals. To delineate the implication of this pathway in AD, we carried out a search on PubMed including PKR/MKK6/p38/MK2/RIPK1, Alzheimer, and therapeutics. The involvement of this signaling pathway in the genesis of AD lesions, including Aβ accumulations and tau phosphorylation as well as cognitive decline, is demonstrated by the reports described in this review. A future combination strategy with kinase inhibitors should be envisaged to modulate the consequences for neurons and other brain cells linked to the abnormal activation of this pathway.     

Iridium complexes incorporating coumarin moiety as catalyst photoinitiators: Towards household green LED bulb and halogen lamp irradiation

Household LED bulbs and halogen lamps are used to promote the ring-opening photopolymerization of epoxides in the presence of a new series of iridium(III) complexes (IrCs) exhibiting enhanced visible light absorption properties through the introduction of a coumarin moiety. These latter complexes are used as catalyst photoinitiators in an oxidative cycle in combination with a silane and an iodonium salt. Remarkably, even under the selected very soft irradiations (e.g. light intensity lower than 2 mW/cm²), excellent polymerization profiles are obtained (conversions > 80%). The mechanisms are investigated by ESR and luminescence experiments.     

Science and animal welfare in France and European Union: Rules,constraints, achievements

The welfare of food-producing animals is a focus of public debate in Europe. Political institutions, have introduced regulations based on scientific data. Meanwhile, the practices of producers and transformers were modified. Implementation of care practices is added to the goal of sustainable basic health of animals. Nevertheless urban consumers still look for the “naturalness” of living animals. A brief historical perspective introduces the building process of European regulations. A short list of Directories and Recommendations provides a clue on the complexity of resulting construct. Now, this complexity is calling for simplification of rules while practices should be compatible with professional constraints. Few selected examples are brought to illustrate how the concepts initially studied by scientists (welfare, pain, stress, “consciousness”/awareness) were integrated in regulations and implemented by producers and meat industry in order to simultaneously maintain the requirements for high quality and security standards. At the same time, free trade market constraints introduced new distortions, in particular those linked to the world demand for proteins. Indeed, the controversy about animal welfare, initially brought on ethical grounds, became a case for ongoing adjustements of EU policy, requesting to combine scientific knowledge on animals, consequent evolution in the representation of animals by urban consumers with the challenge of adaptation and implemention of regulations.     

Complex geometry macroporous SiC ceramics obtained by 3D-printing,polymer impregnation and pyrolysis (PIP) and chemical vapor deposition (CVD)

We present here an original route for the manufacturing of SiC ceramics based on 3D printing, polymer impregnation and pyrolysis and chemical vapor deposition (CVD). The green porous elastomer structures were first prepared by fused deposition modeling (FDM) 3D-printing with a composite polyvinyl alcohol/elastomer wire and soaking in water, then impregnated with an allylhydridopolycarbosilane preceramic polymer. After crosslinking and pyrolysis, the polymer-derived ceramics were reinforced by CVD of SiC using CH₃SiCl₃/H₂ as precursor. The multiscale structure of the SiC porous specimens was examined by X-ray tomography and scanning electron microscopy analyses. Their oxidation resistance was also studied. The pure and dense CVD-SiC coating considerably improves the oxidation resistance.     

Pairwise testing for software product lines: comparison of two approaches

Software Product Lines (SPL) are difficult to validate due to combinatorics induced by variability, which in turn leads to combinatorial explosion of the number of derivable products. Exhaustive testing in such a large products space is hardly feasible. Hence, one possible option is to test SPLs by generating test configurations that cover all possible t feature interactions (t-wise). It dramatically reduces the number of test products while ensuring reasonable SPL coverage. In this paper, we report our experience on applying t-wise techniques for SPL with two independent toolsets developed by the authors. One focuses on generality and splits the generation problem according to strategies. The other emphasizes providing efficient generation. To evaluate the respective merits of the approaches, measures such as the number of generated test configurations and the similarity between them are provided. By applying these measures, we were able to derive useful insights for pairwise and t-wise testing of product lines.     

The multiobjective multidimensional knapsack problem: a survey and a new approach

The knapsack problem (KP) and its multidimensional version (MKP) are basic problems in combinatorial optimization. In this paper, we consider their multiobjective extension (MOKP and MOMKP), for which the aim is to obtain or approximate the set of efficient solutions. In the first step, we classify and briefly describe the existing works that are essentially based on the use of metaheuristics. In the second step, we propose the adaptation of the two‐phase Pareto local search (2PPLS) to the resolution of the MOMKP. With this aim, we use a very large scale neighborhood in the second phase of the method, that is the PLS. We compare our results with state‐of‐the‐art results and show that the results we obtained were never reached before by heuristics for biobjective instances. Finally, we consider the extension to three‐objective instances.