Journal of Next-Generation Research 5.0
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Les voyageuses dans l'océan Indien: XIXe - première moitié du XXe siècle : identités et altérités
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An approximate Jerusalem square whose side equals a Pell number
No full text5 pages, 3 figuresWe take advantage of the properties of the Pell numbers to construct an integer version of the Jerusalem square fractal
Towards a holistic approach for multi-objective optimization of food processes: a critical review
No full textInternational audienceWhile Multi-objective Optimization (MOO) has provided many methods and tools for solving design problems, food processes have benefitted little from them. MOO encompasses the identification of performance indicators, process modelling, preference integration, trade-off assessment, and finding the best trade-offs. In this review, the use of these five elements in the design of food processes through MOO is analysed. A number of studies dealing with food processes MOO have been identified. Even though these studies improve the design process, they often approach MOO in a simplified and insufficiently rationalized way. Based on this review, several research issues are identified, related to the improvement of the different models and methods, and to the development of more holistic MOO methods for food processes
A spatial and environmental analysis of shark attacks on Reunion Island (1980–2017)
No full textInternational audienceThis paper analyses data related to the 57 shark attacks that were recorded on Reunion from 1980 to 2017, against the backdrop of an Indian Ocean island that is particularly vulnerable to shark attacks. To address this issue of vulnerability, the discussion focuses on the respective weight of environmental, contextual and individual variables. The most pertinent parameters to explain the occurrence of attacks on Reunion are as follows: time of day, month and turbidity. Two specific features of Reunion Island can be added to those: first, the high mortality rate of the attacks (46% vs a world average of 11%), and secondly, the average increase in the number of attacks between 2011 and 2017, despite the average drop in the number of ocean users. To understand and explain this rise, three variables are identified: water turbidity, swell height and victim activity.In addition, the multiple correspondence analysis, despite the limited number of attacks, provides correlations between some variables: on the one hand, attack outcome, turbidity, swell height, and, as regards attacks before or after 2011, board sports and swell height
Effects of extraction method and storage of dry tissue on marine lipids and fatty acids
No full textInternational audienceVarious protocols are currently used to study marine lipids, but there is a growing interest in working on dry samples that are easier to transport. However, reference protocols are still lacking for dry samples. In order to make recommendations on this use, lipid classes and fatty acids (FA) obtained from six analytical protocols using two different tissue states (dry vs wet) and three extraction methods (automat vs manual potter vs leaving the solvent to work on tissue) were compared. Three dry storage modes of tissue (freezer vs gas nitrogen vs dry room) during one and three months were also compared. These comparisons were made on seven marine species with different lipid profiles, including fishes, crustaceans and mollusks. Lipid classes and FA obtained from wet and dry tissues were similar, but they were affected by the extraction methods. Regardless of tissue state, “Leave to work” methods obtained the highest lipid quantities, followed by manual potter and automat methods (ca. 90% and 80% of “Leave to work” methods, respectively). Linear relationships allowed correction for lipid classes and FA concentrations obtained from different protocols. The repeatability of all protocols still needs to be improved, especially for fish species. Increasing the replicate number for each sample might be an indirect way to improve lipid quantification. Our results show that storing dry tissues in the freezer for more than one month was associated with a decrease in lipids, which is also observed for other storage methods. For qualitative studies of FA (expressed in %), a three-month storage of dry tissue in freezer did not affect the relative composition of species/tissues with a lipid content below 20% of dry weight
Streamwise streaks induced by bedload diffusion
No full textInternational audienceA fluid flowing over a granular bed can move its superficial grains, and eventually deform it by erosion and deposition. This coupling generates a beautiful variety of patterns such as ripples, bars and streamwise streaks. Here, we investigate the latter, sometimes called "sand ridges" or "sand ribbons". We perturb a sediment bed with sinusoidal streaks, the crests of which are aligned with the flow. We find that, when their wavelength is much larger than the flow depth, bedload diffusion brings mobile grains from troughs, where they are more numerous, to crests. Surprisingly, gravity can only counter this destabilising mechanism when sediment transport is intense enough. Relaxing the long-wavelength approximation, we find that the cross-stream diffusion of momentum mitigates the influence of the bed perturbation on the flow, and even reverses it for short wavelengths. Viscosity thus opposes the diffusion of entrained grains to select the most unstable wavelength. This instability might turn single-thread alluvial rivers into braided channels
Amatus amatam dimisit. Déclaration d'amour et tragédie cachée dans Bérénice de Racine
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