490 research outputs found
Ouvrages en dĂ©bat. La communication environnementale, Thierry Libaert, CNRS Ăditions, 2016
Vingt-deux auteurs ont participĂ© Ă cet ouvrage collectif dirigĂ© par Thierry Libaert, expert en communication des organisations, pour traiter de la question de la communication environnementale. Une partie des intervenants exerce son activitĂ© professionnelle dans le milieu universitaire, lâautre au sein de structures privĂ©es oĂč, malheureusement, Ă certains moments la dĂ©fense dâintĂ©rĂȘts sectoriels, corporatistes a pris le pas sur lâanalyse autocritique. Ce qui en fait dans lâensemble un ouvrage Ă la fois attrayant et contrastĂ©
A PatchMatch-based Dense-field Algorithm for Video Copy-Move Detection and Localization
We propose a new algorithm for the reliable detection and localization of
video copy-move forgeries. Discovering well crafted video copy-moves may be
very difficult, especially when some uniform background is copied to occlude
foreground objects. To reliably detect both additive and occlusive copy-moves
we use a dense-field approach, with invariant features that guarantee
robustness to several post-processing operations. To limit complexity, a
suitable video-oriented version of PatchMatch is used, with a multiresolution
search strategy, and a focus on volumes of interest. Performance assessment
relies on a new dataset, designed ad hoc, with realistic copy-moves and a wide
variety of challenging situations. Experimental results show the proposed
method to detect and localize video copy-moves with good accuracy even in
adverse conditions
[i]Conidames[/i], a new oriental genus of Sycophaginae (Hymenoptera, Agaonidae) associated with [i]Ficus[/i] section Conosycea (Moraceae)
The sycophagines are strictly associated with two subgenera of Fit to L. (Moraceae), namely,Slycomo77/S and Urostignza. They mostly oviposit through the fig wall and lay their eggs within the fig flowers, being either gall-makers or parasitoids of other fig wasps. In this contribution, a new genus of Sycophaginae, [i]Conidarnes[/i] Earache & Rasplus, gen. n., is described with seven new species: [i]Conidarnes achterbergi[/i] Earache & Rasplus, sp. n.; [i]Conidarwes beryl'[/i] Farache & Rasplus, sp. n.; [i]Conidarnes laevis[/i] Earache & Rasplus, sp. n.;[i] Conidames santineloi[/i] Earache & Rasplus, sp. n.; [i]Conidarnes subtectae[/i] Earache & Rasplus, sp. n.; [i]Conidarnes sidcata[/i] Farache & Rasplus, sp. n.; and [i]Conidarnes sumatranae[/i] Farache & Rasplus, sp. n. Illustrations, morphological diagnoses, dichotomous keys and multi-entry online keys to species are provided. [i]Conidarnes[/i] species strictly occur in the oriental region, and their distribution does not oVerlap with the distribution of the two other genera belonging to the same clade. Due to their relative rarity, we encourage extensive sampling of Conosycea figs to improve our knowledge of the genus
Phylogenetic information reveals the peculiarity of Caryedon serratus (Coleoptera, Chrysomelidae, Bruchinae) feeding on Cassia sieberiana DC (Caesalpinioideae)
Studies over the past 20 years on natural populations indicated that sympatric speciation may be far more common and widespread among plants and animals than previously thought. By using molecular phylogenetics (on a combined data set of two genes), the relationships between Caryedon serratus native forms and forms feeding on groundnut was investigated. The specific objectives were to clarify the taxonomic status of C. serratus feeding on Cassia sieberiana DC. Morphological analysis was conducted, using parts of the adult specimens which were dry-mounted for the studies. Morphological study comprised extraction of the genitalia, which were cleared and mounted in Canada balsam following standard procedures. Results showed a strong differentiation of insects from different hosts’ trees, with specimens from C. sieberiana possibly representing a sibling species
First record of a non-pollinating fig wasp (Hymenoptera: Sycophaginae) from Dominican amber, with estimation of the size of its host figs
Fig trees and their pollinating fig wasps arose about 75 million years ago in the Cretaceous period. Several other groups of chalcid wasps also utilize figs for larval development, including sycophagines, the putative sister group to pollinating fig wasps. Whereas stone and amber fossil pollinators are known, no fossils representing non-pollinating fig wasp groups have been confirmed previously. Here, we describe the first Sycophaginae from the c.15â20 Ma Dominican amber, Idarnes thanatos sp. nov. Farache, Rasplus, Pereira and Compton, and discuss its relationships within the Idarnes carme species group. Additionally, we use linear regression to compare body size, ovipositor sheaths length, and host fig size data from extant Idarnes species to estimate the size of its host figs. Idarnes thanatos was most likely associated with small to medium sized figs (diameter â€1.0 cm), that were likely to have been dispersed by birds and primates. The discovery of this close relative of extant non-pollinating fig wasps suggests that early Miocene and modern fig wasp communities may share similar ecological and functional features
Constraints on convergence: hydrophobic hind legs allow some male pollinator fig wasps early access to submerged females
Pollinator fig wasps (Hymenoptera: Agaonidae) display numerous adaptations linked to their obligate association with fig trees (Ficus). Ceratosolen fig wasps pollinate figs that often fill temporarily with liquid, and one clade has males with unusually long hind legs. We investigated their morphology and behaviour. Scanning electron microscopy (SEM) revealed that the cuticle of their hind legs is highly modified and covered with numerous hydrophobic setae and microtrichia that can prevent blockage of the waspsâ large propodeal spiracles by liquids. In deep liquid, the males floated on the surface, but when only a thin layer of liquid was present, the legs allowed males to access females without the risk of drowning. Access to females was facilitated by an air bubble that forms between the hind legs and maintains a column of air between the spiracles and the centre of the figs. Sexual selection should favour males that can gain earlier access to mates, and the modified legs represent an adaptation to achieve this. Convergent adaptations are known in some unrelated non-pollinating fig wasps that develop in similar liquid-filled figs, but these species have enlarged hydrophobic peritremata at the ends of their metasoma to protect the spiracles located there. Unlike non-pollinating fig wasps, pollinator males need to insert their metasoma deep into femalesâ galls during mating. This difference in mating behaviour has constrained the extent of convergence
Multilocus phylogeny and ecological differentiation of the "Eupelmus urozonus species group" (Hymenoptera, Eupelmidae) in the West-Palaearctic
Background: The ecological differentiation of insects with parasitic life-style is a complex process that may involve phylogenetic constraints as well as morphological and/ or behavioural adaptations. In most cases, the relative importance of these driving forces remains unexplored. We investigate here this question for the â Eupelmus urozonus species group â which encompasses parasitoid wasps of potential interest in biological control. This was achieved using seven molecular markers, re liable records on 91 host species and a proxy of the ovipositor length. Results: After using an adequate partitioning scheme, Maximum likelihood and Bayesian approaches provide a well-resolved phylogeny supporting the monophyly of this species group and highlighting its subdivision into three sub-groups. Great variations of both the ovipositor length and the host range (specialist versus generalist) were observed at this scale, with these two features being not significantly constrained by the phylogeny. Ovipositor length was not shown as a significant predictor of the parasitoid host range. Conclusions: This study provides firstly the first evidence for the strong lability of both the ovipositor's length and the realised host range in a set of phylogeneticall y related and sympatric species. In both cases, strong contrasts were observed between sister species. Moreover, no significant correlation was found between these two features. Alternative drivers of the ecological differentiation such as interspecific interactions are proposed and the consequences on the recruitment of these parasitoids on native and exotic pests are discussed
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