Search results for "HS"
showing 10 items of 28320 documents
la prospection systématique d’un fond de rivière : l’exemple du Doubs
2020
La présentation des méthodes mises en œuvre et des résultats obtenus à l’occasion d’une opération de prospection subaquatique systématique menée sur la rivière Doubs, en amont de Verdun-sur-le-Doubs (Saône-et-Loire), illustre en grandeur réelle l’intérêt de la démarche adoptée, fondée sur des principes simples, dans la perspective d’un inventaire systématique du patrimoine fluvial immergé. La diversité des vestiges découverts et leur répartition sur la longue durée en soulignent la pertinence mais également, s’il en était encore besoin, la réalité du formidable potentiel archéologique que recèlent les cours d’eau. The presentation of the methods used and results obtained during a systematic…
Identification of weed community traits response to conservation agriculture
2013
International audience; Conservation agriculture is designed to deliver more sustainable cropping systems by preserving agricultural soils with tillage abandonment. However, knowledge on the impacts of Conservation agriculture adoption on weed infestation level and potential shifts in the composition of weed communities appears low and contradictory. We used a trait-based approach to investigate whether there are shifts in values of a set of traits within weed communities following the adoption of Direct Drilling with cover-crop (DD) which is one of the Conservation Agriculture practices. Weed surveys were conducted across a range of times since conversion to DD in 52 winter wheat fields lo…
Geographic mosaic of selection by avian predators on hindwing warning colour in a polymorphic aposematic moth
2020
AbstractWarning signals are predicted to develop signal monomorphism via positive frequency-dependent selection (+FDS) albeit many aposematic systems exhibit signal polymorphism. To understand this mismatch, we conducted a large-scale predation experiment in four locations, among which the frequencies of hindwing warning coloration of aposematic Arctia plantaginis differ. Here we show that selection by avian predators on warning colour is predicted by local morph frequency and predator community composition. We found +FDS to be strongest in monomorphic Scotland, and in contrast, lowest in polymorphic Finland, where different predators favour different male morphs. +FDS was also found in Geo…
Planting Systems for Modern Olive Growing: Strengths and Weaknesses
2021
The objective of fully mechanizing olive harvesting has been pursued since the 1970s to cope with labor shortages and increasing production costs. Only in the last twenty years, after adopting super-intensive planting systems and developing appropriate straddle machines, a solution seems to have been found. The spread of super-intensive plantings, however, raises serious environmental and social concerns, mainly because of the small number of cultivars that are currently used (basically 2), compared to over 100 cultivars today cultivated on a large scale across the world. Olive growing, indeed, insists on over 11 million hectares. Despite its being located mostly in the Mediterranean countr…
Lobesia botrana larvae develop faster in the presence of parasitoids.
2013
3 pages; International audience; To combat parasitism hosts often rely on their immune system, which is the last line of defense. However, the immune system may not always be effective, and other non-immunological defenses might be favored to reduce the cost of parasite infection. Here we report that larvae of the moth Lobesia botrana can rapidly accelerate their development and reach maturity earlier in response to cues perceived at a distance from parasitoids. Such a phenotypically plastic life history shift, induced by the perception of deadly enemies in the environment, is likely to be an adaptive defensive strategy to prevent parasitoid attack, and has important implications in host-pa…
Gauge theory of the long-range proximity effect and spontaneous currents in superconducting heterostructures with strong ferromagnets
2017
We present the generalized quasiclassical theory of the long-range superconducting proximity effect in heterostructures with strong ferromagnets, where the exchange splitting is of the order of Fermi energy. In the ferromagnet the propagation of equal-spin Cooper pairs residing on the spin-split Fermi surfaces is shown to be governed by the spin-dependent Abelian gauge field which results either from the spin-orbital coupling or from the magnetic texture. This additional gauge field enters into the quasiclassical equations in superposition with the usual electromagnetic vector potential and results in the generation of spontaneous superconducting currents and phase shifts in various geometr…
Online Scheduling of Task Graphs on Hybrid Platforms
2018
Modern computing platforms commonly include accelerators. We target the problem of scheduling applications modeled as task graphs on hybrid platforms made of two types of resources, such as CPUs and GPUs. We consider that task graphs are uncovered dynamically, and that the scheduler has information only on the available tasks, i.e., tasks whose predecessors have all been completed. Each task can be processed by either a CPU or a GPU, and the corresponding processing times are known. Our study extends a previous \(4\sqrt{m/k}\)-competitive online algorithm [2], where m is the number of CPUs and k the number of GPUs (\(m\ge k\)). We prove that no online algorithm can have a competitive ratio …
Applying Biomimicry to Cities: The Forest as Model for Urban Planning and Design
2021
International audience; The idea of applying biomimicry to cities is attracting increasing attention as a way of achieving sustainability. Undoubtedly the most frequently evoked natural model in this context is the forest, though it has not yet been investigated with any great scientific rigour. To overcome this lacuna, we provide: first, a justification of the model of the forest via what we call the arguments from “fittingness”, “scale”, and “complexity”; second, an exploration of various key innovations made possible by this model in the fields of urban planning, urban water systems, urban energy and transport systems, and urban food and nutrient systems.
District heating networks: enhancement of the efficiency
2019
International audience; During the decades the district heating's (DH) advantages (more cost-efficient heat generation and reduced air pollution) overcompensated the additional costs of transmission and distribution of the centrally produced thermal energy to consumers. Rapid increase in the efficiency of low-power heaters, development of separated low heat density areas in cities reduce the competitiveness of the large centralized DH systems in comparison with the distributed cluster-size networks and even local heating. Reduction of transmission costs, enhancement of the network efficiency by optimization of the design of the DH networks become a critical issue. The methodology for determ…
The tougher the environment, the harder the adaptation? A psychological point of view in extreme situations
2021
IF: 2.8 (Q1); International audience; Grounded within a multidimensional and multilevel approach, the aim of this study was to investigate the time course of Psychological Adaptation Process (PAP) dimensions (social, emotional, occupational, and physical) during one-year polar winter-overs in Subantarctic and Antarctic stations. The effects of perceived control (PC) at the start of polar winter on the dynamics of the PAP dimensions were also examined. The present findings clarify some changes in PAP in extreme environments: (a) The dimensions of psychological adaptation evolved differently as a function of environmental conditions; and (b) PC influenced the trajectories of PAP dimensions. T…