Search results for "model."
showing 10 items of 23664 documents
Why aren't warning signals everywhere? : On the prevalence of aposematism and mimicry in communities
2021
Warning signals are a striking example of natural selection present in almost every ecological community - from Nordic meadows to tropical rainforests, defended prey species and their mimics ward off potential predators before they attack. Yet despite the wide distribution of warning signals, they are relatively scarce as a proportion of the total prey available, and more so in some biomes than others. Classically, warning signals are thought to be governed by positive density-dependent selection, i.e. they succeed better when they are more common. Therefore, after surmounting this initial barrier to their evolution, it is puzzling that they remain uncommon on the scale of the community. He…
Eco-genetics of desiccation resistance in Drosophila.
2021
International audience; Climate change globally perturbs water circulation thereby influencing ecosystems including cultivated land. Both harmful and beneficial species of insects are likely to be vulnerable to such changes in climate. As small animals with a disadvantageous surface area to body mass ratio, they face a risk of desiccation. A number of behavioural, physiological and genetic strategies are deployed to solve these problems during adaptation in various Drosophila species. Over 100 desiccation-related genes have been identified in laboratory and wild populations of the cosmopolitan fruit fly Drosophila melanogaster and its sister species in large-scale and single-gene approaches…
Limnology and Aquatic Microbial Ecology of Byers Peninsula: A Main Freshwater Biodiversity Hotspot in Maritime Antarctica
2019
Here we present a comprehensive review of the diversity revealed by research in limnology and microbial ecology conducted in Byers Peninsula (Livingston Island, South Shetland Islands, Antarctica) during the last two decades. The site constitutes one of the largest ice-free areas within the Antarctic Peninsula region. Since it has a high level of environmental protection, it is less human-impacted compared to other sites within the South Shetland archipelago. The main investigations in Byers Peninsula focused on the physical and chemical limnology of the lakes, ponds, rivers, and wetlands, as well as on the structure of their planktonic and benthic microbial communities, and on the function…
Risk of Invasive Lupinus polyphyllus Seed Survival in Biomass Treatment Processes
2021
Invasive plant species threaten native species and habitats causing ecologic, economic and social burden. When creating climate friendly solutions by utilizing plant biomasses in biogas and fertilizer production, safety should be ensured concerning the use of residues. This study concentrates on the treatment of biomasses containing invasive plant material by tunnel and windrow composting, and by farm-scale and laboratory-scale anaerobic digestion (AD) in mesophilic conditions. Germination of the nationally settled and harmful invasive species Lupinus polyphyllus Lindl. was investigated after these processes. In addition, the role of the conditions found in the processes that destroyed seed…
Impact loading history modulates hip fracture load and location : A finite element simulation study of the proximal femur in female athletes
2018
Sideways falls impose high stress on the thin superolateral cortical bone of the femoral neck, the region regarded as a fracture-prone region of the hip. Exercise training is a natural mode of mechanical loading to make bone more robust. Exercise-induced adaptation of cortical bone along the femoral neck has been previously demonstrated. However, it is unknown whether this adaption modulates hip fracture behavior. The purpose of this study was to investigate the influence of specific exercise loading history on fall-induced hip fracture behavior by estimating fracture load and location with proximal femur finite element (FE) models created from magnetic resonance images (MRI) of 111 women w…
Rocking of rigid block on nonlinear flexible foundation
2017
Abstract The two prime models used currently to describe rocking of rigid bodies, the Housner’s model and the Winkler foundation model, can capture some of the salient features of the physics of this important problem. These two models involve either null or linear interaction between the block and the foundation. Hopefully, some additional aspects of the problem can be captured by an enhanced nonlinear model for the base-foundation interaction. In this regard, what it is adopted in this paper is the Hunt and Crossley’s nonlinear impact force model in which the impact/contact force is represented by springs in parallel with nonlinear dampers. In this regard, a proper mathematical formulatio…
Two-Dimensional Numerical Modelling of a Moored Floating Body under Sloping Seabed Conditions
2020
A coupled floating body-mooring line model is developed by combining a boundary element model for a two-dimensional floating body and a catenary mooring line model. The boundary element model is formulated in the time domain by a continuous Rankine source, and a reflection potential is introduced to account for the wave reflection due to sloping seabed. This newly developed model is validated by comparisons against available data. Then, dynamic response analyses are performed for the moored body in various seabed conditions. Compared with a flat seabed, a sloping seabed causes unsymmetrical mooring line configuration and generates noticeable effects in the motion responses of the floating b…
A Sequential Game Approach for Computation-Offloading in an UAV Network
2017
International audience; Small drones are currently emerging as versatile nascent technology that can be used in exploration and surveillance missions. However, most of the underlying applications require very often complex and time-consuming calculations. Although, the limited resources available onboard the small drones, their mobility, the computation delays and energy consumption make the operation of these applications very challenging. Nevertheless, computation-offloading solutions provide feasible resolves to mitigate the issues facing these constrained devices. In this context, we address in this paper the problem of offloading highly intensive computation tasks, performed by a fleet…
Teachers’ intention to use educational video games: The moderating role of gender and age
2018
Educational video games represent an educational change that challenges teachers and managers of Higher Education institutions in several ways including their attitude formation and behavioural intention. Using a Technology Acceptance Model (TAM) approach a research model is developed to predict teachers’ behavioural intention to use educational video games in their courses. The research model is tested via structural equation modelling (SEM) on a sample of 312 Higher Education teachers. Main results suggest that perceived usefulness influences in a direct and positive way teachers’ behavioural intention while perceived ease of use indirectly influences intention through perceived usefulnes…
Usability and acceptability assessment of an empathic virtual agent to prevent major depression
2016
In Human-Computer Interaction, the adaptation of the content and the way of how this content is communicated to the users in interactive sessions is a critical issue to promote the acceptability and usability of any computational system. We present a user-adapted interactive platform to identify and provide an early intervention for symptoms of depression and suicide. In particular, we describe the work performed to assess users' system acceptability and usability. An empathic Virtual Agent is the main interface with the user, and it has been designed to generate the appropriate dialogues and emotions during the interactions according to the detected user's specific needs. This personalizat…