Science & Mathematics

(Uploaded by Plazi from the Biodiversity Heritage Library) No abstract provided.

(Uploaded by Plazi from the Biodiversity Heritage Library) No abstract provided.

(Uploaded by Plazi from the Biodiversity Heritage Library) No abstract provided.

This study investigates the effects of four preservation treatments: thermal pasteurization (TP), ohmic heating (OH), high-pressure processing (HPP), and pulsed electric fields (PEF), on the aroma and phenolic compounds of strawberry nectar, under equivalent microbial inactivation conditions (5-log reduction) on pilot-scale systems. Changes during 60 days of storage at 4 • C were also evaluated. HPP was the most effective method for retaining aroma compounds, with initial levels of 5.29 ± 0.03 mg/L, closely to the untreated samples, while TP showed the lowest retention (2.94 ± 0.13 mg/L). During storage, HPP-treated samples had a 41.6 % reduction in aroma compounds but still the highest remaining concentrations after storage compared to the other treatments. Key aroma markers, such as mesifurane, methyl and ethyl butyrate, were significantly better preserved in HPP and PEF treated samples compared to TP and OH. Phenolic content followed a similar trend: immediately after treatment HPP and PEF samples exhibited the highest total phenolic content (TPC), including anthocyanins like pelargonidin-3-glucoside, which constituted up to 81 % of total anthocyanins. Non-thermal methods (HPP and PEF) preserved phenolics better than TP, although differences between treatments were not significant after 60 days of storage. OH demonstrated intermediate performance due to its uniform heating process that minimized

24x36 mm, gélatine plan-film.

The influence of ionizing radiation on clay mineraIs is poorly known, in spite of their use as a major component of the engineered barrier in High Level Nuclear Waste Repositories (HLNWR). In tbis context, the production of H$_2$ by clay minerals under ionizing radiation could be a real issue. It can, e.g., lead to the loss of radionuclide retention properties by creating cracks in the engineered barrier. It is thus important to determine H$_2$ formation reaction mechanisms and to understand the role of several parameters on this production, such as the water amount, the presence of impurities and the nature of the clay mineraI. We studied synthetic clay mineraIs (talc, which has no water molecules, montmorillonite and saponite which exhibit charge excess in different locations) [1-2] and also natural montmorillonites from Camp Berteau [3]. The reactivity under electron irradiation is deciphered thanks to H$_2$ production measurements at well-defined relative humidities together with electron spin resonance experiments that allow detecting the defects created upon irradiation. Comparing the reactivity induced in the synthetic samples enables understanding the impact of the presence of two-dimensionally confmed water molecules and the influence of the charge location in the sheets of the clay mineraI. Moreover, the comparison between synthetic and natural talc evidences the strong role played by impurities on the H$_2$ production yields [1]. We find that H$_2$ production is due to the presence of structural-OH groups and that the confmement of water molecules is a crucial factor. Moreover, the charge location in the sheets of the clay mineraIs plays only a marginal role [1-2]. AlI these results will be discussed and the corresponding reaction mechanisms will be presented. Lastly, the role of impurities in natural clay mineraIs such as Fe$^{3+}$ that strongly decrease the H$_2$ production will be discussed.

Reservoir heterogeneities can severely affect the effectiveness of waterflooding because displacing fluids tend to flow along high-permeability paths and prematurely breakthrough at producing wells. A Proof-of-Concept (PoC) study is presented while discussing the experimental results of a research on “core-shell” technology to improve waterflooding in heterogeneous oil reservoirs. The proposed methodology consists in injecting a water dispersion of nanocapsules after the reservoir has been extensively flushed with water. The nanocapsules are made of a “core” (either polymeric or siliceous materials), protected by a “shell” that can release its content at an appropriate time, which activates through gelation or aggregation thus plugging the high permeability paths. Additional flooding with water provides recovery of bypassed oil. The initial conceptual screening of possible materials was followed by extensive batch and column lab tests. Then, 3D dynamic simulations at reservoir scale were performed to compensate for the temporary lack of pilot tests and/or field applications.

Dans cet article, nous étudions certains aspects que peut prendre le processus de classification dans le cadre des systèmes de représentation de connaissances par objets. Nous nous intéressons essentiellement aux opérations de classification de classes et d'instances. Nous évoquons ensuite trois applications particulièrement importantes dans le cadre de la conception de systèmes intelligents qui reposent toutes trois sur le processus de classification : la formation incrémentale de classes et de hiérarchies de classes, l'extraction de connaissances à partir de bases de données et le raisonnement à partir de cas.

We experimentally investigate the operation of a cost-effective wavelength-division-multiplexed passive optical network (WDM-PON) based on wavelength-locked Fabry-Pérot laser diodes (FP-LDs). A single quantum-dash passively mode-locked laser (QD-MLL) is combined with an arrayed waveguide grating in WDM-PON architecture to provide a low-noise, coherent multiwavelength seeding source to injection-lock the FP-LDs for both downstream and upstream. The results show that the QD-MLL-injected FP-LD has the same performance when compared to the case of injection-locking by a low-noise external cavity laser. Error-free bidirectional transmission over 25 km for 16 channels with 42.7-GHz channel spacing is demonstrated at 2.5 Gb/s in the C-band and an optical budget higher than 30 dB is reached.

L'objet de ce travail est d'examiner les relations (substituabilite, complementarite) existant entre le prix des produits riches en proteines sur le marche de Rotterdam. Pour cela la methode CKS d'analyse des causalites a ete utilisee. Cette methode permet d'identifier un modele VAR, constitue des prix de ces produits. L'analyse des multiplicateurs permet alors de preciser les relations de substitution entre ces produits.

Les initiatives développées depuis les années 1980 en faveur des "quartiers défavorisés" ont connu une étrange destinée. Tandis que l'habitat était à l'origine des mesures adoptées pour améliorer la situation dans ces quartiers, le traitement de cette dimension, qui pourtant absorbe en moyenne les deux tiers des crédits affectés aux diverses opérations engagées sur ces quartiers, semble presque devenu marginal dans cette approche qu'on appelle désormais la "politique de la ville". Elle est devenue la parade, la plus appropriée, pense-t-on, contre les risques qui pèsent sur la paix sociale. Les choses sont sans doute moins simples lorsqu'on les regarde d'en bas. Un ensemble de logiques accumulées, qui relèvent de la nature du parc de logement, de sa fonction sociale, de sa valeur marchande, de son peuplement, de son histoire, mais aussi de sa forme, de sa dimension, de sa localisation comme de son impact dans l'imaginaire social, a contribué à fabriquer ces lieux de réclusion. Cette représentation est entièrement rapportée à la population la plus en difficulté de ces quartiers, et confond avec elle les familles sans autre problème que la modestie de leur condition, familles souvent anciennes dans le quartier, installées là parce que les HLM étaient dans les années 1960 la réponse la plus appropriée à la recherche d'un logement confortable. A partir de situations, soit distanciées, soit impliquées, de recherche, d'expertise ou d'administration associative, ce sont les écarts propres à ces diversités interne (à l'intérieur du quartier) et externe (d'un quartier à l'autre), que l'auteur tente de pointer ici.

Despite the advancements in developing markerless gait analysis systems, they still demonstrate lower accuracy compared to gold-standard systems. Hence, in this research, a novel approach is presented to improve the lower limb kinematics accuracy in markerless gait analysis. This approach refines the 3D lower-limb skeletons obtained by AI-based pose estimation algorithms in a subject-specific geometric manner, preserves skeleton links’ length, benefits from gait phases information that adds biomechanical awareness to the algorithm, and utilizes an embedded trajectory smoothing. Validation of the proposed method shows that it reduces 12.6%-43.5% of root mean square error (RMSE) and significantly improves kinematic curves’ similarity to the gold-standard ones. Results also prove the feasibility of more accurate lower limb kinematics calculation using a single (2.02°-7.57° RMSE) or dual RGB-D camera (1.66°-7.25° RMSE). Development of such algorithms could result in requirement of fewer cameras that deliver comparable or even superior measurement accuracy compared to multi-camera approaches.