Search results for "cam"
showing 10 items of 4055 documents
Faster acquisition of symbiotic partner by common mycorrhizal networks in early plant life stage
2016
Arbuscular mycorrhizal (AM) fungi usually improve plant performance yet our knowledge about their effects on seed germination and early plant establishment is very limited. We performed a factorial greenhouse experiment where the seeds from four low Arctic cooccurring mycorrhizal herbs (Antennaria dioica, Campanula rotundifolia, Sibbaldia procumbens, and Solidago virgaurea) were germinated alone or in the vicinity of an adult Sibbaldia plant with or without AM fungi; given either as spores or being present in a common mycorrhizal network (CMN). Three different AM fungal species were examined to assess species-specific differences in symbiont acquisition rate. Out of the four plant species i…
Camouflage accuracy in Sahara–Sahel desert rodents
2020
1. Camouflage helps animals to hide from predators and is therefore key to survival. Although widespread convergence of animal phenotypes to their natural environment is well-established, there is a lack of knowledge about how species compromise camouflage accuracy across different background types in their habitat.2. Here we tested how background matching has responded to top–down selection by avian and mammalian predators using Sahara–Sahel desert rodents in North Africa.3. We show that the fur colouration of several species has become an accurate match to different types of desert habitats. This is supported by a correlation analysis of colour and pattern metrics, investigation of animal…
Tracking the invasion of the red swamp crayfish Procambarus clarkii (Girard, 1852) (Decapoda Cambaridae) in Sicily: a “citizen science” approach
2017
Author(s): Faraone, Francesco Paolo; Giacalone, Gabriele; Canale, Domenica Emanuela; D'Angelo, Stefania; Favaccio, Giorgio; Garozzo, Vincenzo; Giancontieri, Giacoma Lidia; Isgro, Carmelo; Melfi, Raffaella; Morello, Bruno; Navarria, Federica; Russo, Giuseppe; Tinnirello, Viviana; Torre, Antonio; Torre, Daniele; Torre, Giancarlo; Urso, Giuseppe; Vinci, Pierluigi; Zizzo, Maria Grazia; Marrone, Federico | Abstract: The first record of the red swamp crayfish in Sicily dates back to 2003 and, since then, the species seemed to be confined to a few localities in western Sicily. A small “citizen science” project carried out from November 2016 onwards led to the creation of the “Sicilian Procambarus …
Record of a 10-year old European Wildcat Felis silvestris silvestris Schreber, 1777 (Mammalia: Carnivora: Felidae) from Mt. Etna, Sicily, Italy
2020
Longevity data for wild felids are lacking in the literature. Here we report a camera trap recapture of a European Wildcat Felis silvestris at Mt. Etna in Sicily, Italy after nine years. This individual was clearly identifiable as its tail ended with a white ring rather than the typical black ring and had a unique shape of the dorsal stripe. At first capture on 26 May 2009, this cat was assessed as an adult, so that the likely minimum age of this individual at the time of recapture on 10 June 2018 must have been be at least 10 years. This finding represents the oldest known European Wildcat in the wild and provides insight into age structure in wildcat populations.
The Influence of Solar Power Plants on Microclimatic Conditions and the Biotic Community in Chilean Desert Environments
2016
The renewable energy sector is growing at a rapid pace in northern Chile and the solar energy potential is one of the best worldwide. Therefore, many types of solar power plant facilities are being built to take advantage of this renewable energy resource. Solar energy is considered a clean source of energy, but there are potential environmental effects of solar technology, such as landscape fragmentation, extinction of local biota, microclimate changes, among others. To be able to minimize environmental impacts of solar power plants, it is important to know what kind of environmental conditions solar power plants create. This study provides information about abiotic and biotic conditions i…
Direct exposure to solar radiation causes radial growth eccentricity at the beginning of the growing season in Robinia pseudoacacia
2020
Abstract Our study investigated the effect of stem temperature increase on xylem formation in Robinia pseudoacacia tree-trunks, caused by direct exposure to solar radiation. It is important to determine factors which may improve the concentricity of deposited wood tissue and intensify xylogenesis because a strong irregularity of wood tissue deposited in the radial direction in mature trees of R. pseudoacacia reduces the commercial value of the wood. Samples of vascular cambium along with adjacent tissues were collected from the southern (illuminated) and northern (shaded) side of tree-trunks growing in the inner and peripheral (thus exposed to direct sunlight) zones of the research plot. Sa…
Preliminary design process for an adaptive winglet
2017
In the framework of Clean Sky 2 Airgreen 2 GRA ITD project, this paper deals with the design process of a morphing winglet for a regional aircraft. By improving A/C aerodynamic efficiency in off-design flight conditions, the morphing winglet is expected to operate during long (cruise) and short (climb and descent) mission phases to reduce aircraft drag and optimize lift distribution, while providing augmented roll and yaw control capability. The mechanical system is designed to face different flight situations by a proper action on the movable parts represented by two independent and asynchronous control surfaces with variable camber and differential settings. A set of suitable electromecha…
Analytical approach extending the Granier method to radial sap flow patterns
2020
Abstract The Granier thermal dissipation (TD) method is probably the most applied method to compute the transpiration flux of trees, due to its simplicity and effective compromise between theory and data availability. Starting from the heat transfer equations at the basis of Granier’s method, the objective of this paper is to derive an analytical solution for the transpiration flux to extend the sap flow equations to the radial domain. We adopted a flexible approach to cope with the differences in radial sapflow density (SFD) profile shapes that are known to occur in relation to wood anatomy (diffuse porous vs. ring- or non-porous xylem). With this purpose, we investigated the robustness of…
Omnidirectional vision for UAV: applications to attitude, motion and altitude estimation for day and night conditions
2012
International audience; This paper presents the combined applications of omnidirectional vision featuring on its application to aerial robotics. Omnidirectional vision is first used to compute the attitude, altitude and motion not only in rural environment but also in the urban space. Secondly, a combination of omnidirectional and perspective cameras permits to estimate the altitude. Finally we present a stereo system consisting of an omnidirectional camera with a laser pattern projector enables to calculate the altitude and attitude during the improperly illuminated conditions to dark environments. We demonstrate that omnidirectional camera in conjunction with other sensors is suitable cho…
Visual contact with catadioptric cameras
2015
Abstract Time to contact or time to collision (TTC) is utmost important information for animals as well as for mobile robots because it enables them to avoid obstacles; it is a convenient way to analyze the surrounding environment. The problem of TTC estimation is largely discussed in perspective images. Although a lot of works have shown the interest of omnidirectional camera for robotic applications such as localization, motion, monitoring, few works use omnidirectional images to compute the TTC. In this paper, we show that TTC can be also estimated on catadioptric images. We present two approaches for TTC estimation using directly or indirectly the optical flow based on de-rotation strat…