23 research outputs found
Seed Spillage from Grain Trailers on Road Verges during Oilseed Rape Harvest: An Experimental Survey
Context: Anthropogenic vectors enhance the natural dispersal capacity of plant seeds significantly in terms of quantity and distance. Human-mediated seed dispersal (i.e. anthropochory) greatly increases the dispersal of crop species across agroecosystems. In the case of oilseed rape (OSR), spillage of seeds from grain trailers during harvest has never been quantified. Methods: Our experimental approach involved establishing 85 seed trap-sites on the road verges of an agricultural area around the grain silo of Selommes (Loir-et-Cher, France). We recorded OSR spillage during harvest and applied a linear model to the data. Results: The amount of seed spilled was related positively to the area of the OSR fields served by the road, whereas the amount of seed spilled decreased with other variables, such as distance from the trap-site to the verge of the road and to the nearest field. The distance to the grain silo, through local and regional effects, affected seed loss. Local effects from fields adjacent to the road resulted in a cumulative spillage on one-lane roads. On two-lane roads, spillage was nearly constant whatever the distance to the silo due to a mixture of these local effects and of grain trailers that joined the road from more distant fields. From the data, we predicted the number of seeds lost from grain trailers on one road verge in the study area. We predicted a total spillage of 2.05610 6 seeds (64.76610 5) along the road length, which represented
Seed spillage from grain trailers on road verges during oilseed rape harvest: an experimental survey
National audienc
An automatic kriging machine learning method to calibrate meta-heuristic algorithms for solving optimization problems
For years, meta-heuristic algorithms have been widely studied and many improved versions have been developed: from the evolution of the swarm topologies of the Particle Swarm Optimization algorithm, to the using of machine learning to Differential Evolutionary algorithms. However, the tuning of the fundamental meta-heuristic parameters has been less studied, but may lead to significant improvements on the convergence accuracy of these algorithms. This paper aims at developing an automated methodology to calibrate the parameters of population-based meta-heuristic algorithms for optimization problems. Based on the kriging estimation of the best combination of parameters, the Automated parameter tuning of Meta-heuristics (AptM) methodology gives the optimal algorithm setup for each considered problem in order to lead to a better convergence accuracy. The proposed AptM methodology is used to tune three different meta-heuristic algorithms, each applied to twelve mathematical unimodal or multimodal objective functions. AptM methodology performance is assessed by comparison of classical setups usually used in the literature. The numerical results show that the AptM methodology allows a significant improvement of the convergence accuracy of meta-heuristics with an average improvement of 62.02%, 69.12% and 64.94% on optimization problems defined in dimensions 10, 30 and 50 respectively. An experimental criterion is defined based on the convergence accuracy of the AptM methodology over the classical setups, assessing the AptM performances. The previous experimental criterion allows to compare the AptM methodology over the base-set. The AptM methodology shows a significant improvement of the algorithms performance on 97.2% of the tested problems
Unique silica polymorph obtained under electron irradiation
International audienceHigh purity synthetic silica glass (Suprasil F300) samples were densified by High Pressure/High Temperature (HP-HT) using three different pressure/temperature/duration values. Their relaxation process was studied by applying 2.5 MeV electron irradiation with doses varying from 1 MGy up to 11 GGy. At very high dose (11 GGy), all the densified silica samples exhibit the same density value (∼2.26 g/cm3) regardless of the densification conditions, referring to an equilibrium value known as an amorphous silica metamict phase. In detail, the HP-HT silica samples were progressively dedensified from 1 GGy irradiation dose until reaching this equilibrium. Whatever the initial topological disorder revealed through Raman spectra, all silica samples present identical Raman spectra at 11 GGy, with high intensities of D1 and D2 components, attesting they reach one unique silica polymorph. Regarding the irradiation at high temperature (600 MGy, 600 K), the results show that the thermal annealing during irradiation “accelerates” somehow the relaxation kinetics of both macroscopic density and vibrational signature. Furthermore, it seems that such high irradiation temperatures lead to increase the Non-Bridging Oxygen Hole Center point defects generation
Relaxation study of pre-densified silica glasses under 2.5 MeV electron irradiation
Abstract We examined the “relaxation properties” of pre-densified synthetic fused silica glass under 2.5 MeV electron irradiation. The densification of the glass was either obtained by hot compression (5 GPa-350 °C and 5 GPa-1000 °C) or via a thermal treatment increasing its fictive temperature (Tf = 1050, 1250 and 1400 °C). Under irradiation, the pre-densified silica glasses exhibit a relaxation of their macroscopic density with increasing integrated dose. Density was reduced for hot compressed silica and increased for Tf samples with different relaxation rates but it is remarkable that all sample densities follow a trend towards the same equilibrium value around 2.26 for a dose larger than 10 GGy despite a different final topology. After irradiation of hot compressed silica, the Raman spectra display a significant increment of 4 and almost 3-membered rings whereas they exhibit a glass density reduction; demonstrating that a D2 band increase cannot be considered as an absolute marker of the glass compaction. The correlation between density and D2 intensity remains valid until silica density remains lower than 2.26. In contrast, the FWHM of the main band peaking at 440 cm−1 appears to remain correlated to the silica glass density for all investigated samples
Summary of the linear model describing relationships between the natural logarithm of seeds lost +1 and landscape elements.
.<p>≤10%;</p>*<p>≤5%;</p>**<p>≤1%;</p>***<p>≤0.1%.</p><p>On a two-lane road, when <i>Dist_field</i> is 0 m, the expected response equals (4.259−0.617)+9.93×10<sup>−3</sup>⋅<i>Surface_OSR</i>−0.470×ln(<i>Dist_road</i>)+(−4.45×10<sup>−4</sup>+2.95×10<sup>−4</sup>)⋅<i>Dist_Silo</i> = 3.642+9.93×10<sup>−3</sup>⋅<i>Surface_OSR</i>−0.470×ln(<i>Dist_road</i>)−1.491×10<sup>−4</sup> ⋅<i>Dist_Silo</i>.</p
Global map of the Selommes area with daily barplots of OSR seed collected at each trap-site location.
<p>Seed amounts are ln(<i>x</i>+1) transformed; all barplot axes have the same scale between 0 and 8 (which indicates 0 to 2980 seeds). Each trap-site is associated with a number. Each road is represented by an R-number code. D1 is the first day of the survey and D8 the last day.</p
Immunomodulatory and Antioxidant Properties of <i>Ipomoea batatas</i> Flour and Extracts Obtained by Green Extraction
Sweet potato (SP), Ipomoea batatas Lam, belongs to the Convolvulaceae family. It produces edible storage roots. Currently, orange varieties contribute to improving food systems and managing vitamin A deficiency. Processing of this food crop into flour allows better conservation. However, nutrition health data regarding SP flour obtained by green extraction remains scarce. In this study, we therefore explored its phytochemistry and its associated bioactivity potential for human health. We analyzed the nutritional composition of orange flesh sweet potato (OFSP) flour and assessed the antioxidant (free radical scavenging) and immunomodulatory (on inflammatory murine macrophages) properties of the extract. More specifically, we measured the impact of OFSP flour extract on mediators such as Nitric Oxide (NO) and the production of pro-inflammatory cytokines such as Interleukin-6 (IL-6), Tumor Necrosis Factor alpha (TNF-alpha), Monocyte Chemoattractant Protein-1 (MCP-1), and Prostaglandin-E2 (PGE-2). Our results indicated significant fiber, mineral, beta-carotene, and polyphenols content in the extracts, and antioxidant and immunomodulatory bioactivities were also demonstrated with a concentration-dependent inhibition of cytokine production. Taken together, our results suggest that Ipomoea batatas flour could, in addition to being a good source of energy and beta-carotene provitamin A, constitute a food of interest for the prophylaxis of metabolic diseases associated with an underlying low-grade inflammatory state
Cartoons to improve young children's cooperation with inhaled corticosteroids: A preliminary study
Friction mechanisms of Ni-based and Zr-based bulk metallic glasses under different contact pressures
International audienc