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Search Results: 1 - 10 of 3337 matches for " Claude Everaerts "
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Drosophila Cuticular Hydrocarbons Revisited: Mating Status Alters Cuticular Profiles
Claude Everaerts,Jean-Pierre Farine,Matthew Cobb,Jean-Fran?ois Ferveur
PLOS ONE , 2012, DOI: 10.1371/journal.pone.0009607
Abstract: Most living organisms use pheromones for inter-individual communication. In Drosophila melanogaster flies, several pheromones perceived either by contact/at a short distance (cuticular hydrocarbons, CHs), or at a longer distance (cis-vaccenyl acetate, cVA), affect courtship and mating behaviours. However, it has not previously been possible to precisely identify all potential pheromonal compounds and simultaneously monitor their variation on a time scale. To overcome this limitation, we combined Solid Phase Micro-Extraction with gas-chromatography coupled with mass-spectrometry. This allowed us (i) to identify 59 cuticular compounds, including 17 new CHs; (ii) to precisely quantify the amount of each compound that could be detected by another fly, and (iii) to measure the variation of these substances as a function of aging and mating. Sex-specific variation appeared with age, while mating affected cuticular compounds in both sexes with three possible patterns: variation was (i) reciprocal in the two sexes, suggesting a passive mechanical transfer during mating, (ii) parallel in both sexes, such as for cVA which strikingly appeared during mating, or (iii) unilateral, presumably as a result of sexual interaction. We provide a complete reassessment of all Drosophila CHs and suggest that the chemical conversation between male and female flies is far more complex than is generally accepted. We conclude that focusing on individual compounds will not provide a satisfactory understanding of the evolution and function of chemical communication in Drosophila.
Volatile Drosophila Cuticular Pheromones Are Affected by Social but Not Sexual Experience
Jean-Pierre Farine, Jean-Fran?ois Ferveur, Claude Everaerts
PLOS ONE , 2012, DOI: 10.1371/journal.pone.0040396
Abstract: Recognition of conspecifics and mates is based on a variety of sensory cues that are specific to the species, sex and social status of each individual. The courtship and mating activity of Drosophila melanogaster flies is thought to depend on the olfactory perception of a male-specific volatile pheromone, cis-vaccenyl acetate (cVA), and the gustatory perception of cuticular hydrocarbons (CHs), some of which are sexually dimorphic. Using two complementary sampling methods (headspace Solid Phase Micro-Extraction [SPME] and solvent extraction) coupled with GC-MS analysis, we measured the dispersion of pheromonal CHs in the air and on the substrate around the fly. We also followed the variations in CHs that were induced by social and sexual interactions. We found that all CHs present on the fly body were deposited as a thin layer on the substrate, whereas only a few of these molecules were also detected in the air. Moreover, social experience during early adult development and in mature flies strongly affected male volatile CHs but not cVA, whereas sexual interaction only had a moderate influence on dispersed CHs. Our study suggests that, in addition to their role as contact cues, CHs can influence fly behavior at a distance and that volatile, deposited and body pheromonal CHs participate in a three-step recognition of the chemical identity and social status of insects.
Search for electroweak SUSY production at CMS
Pieter Everaerts
Physics , 2014,
Abstract: Using the data collected during Run I of LHC operation the CMS Collaboration performed multiple analyses searching for the direct electroweak production of supersymmetric particles in proton-proton collisions. Different decay modes of the gauginos and sleptons were considered, through intermediate vector bosons or Higgs bosons, or directly to leptons. A set of complementary searches were designed to target these different decays. None of these searches shows any indication for physics beyond the standard model.
Fatty-Acid Preference Changes during Development in Drosophila melanogaster
Anne-Sophie Fougeron, Jean-Pierre Farine, Justin Flaven-Pouchon, Claude Everaerts, Jean-Fran?ois Ferveur
PLOS ONE , 2011, DOI: 10.1371/journal.pone.0026899
Abstract: Fatty-acids (FAs) are required in the diet of many animals throughout their life. However, the mechanisms involved in the perception of and preferences for dietary saturated and unsaturated FAs (SFAs and UFAs, respectively) remain poorly explored, especially in insects. Using the model species Drosophila melanogaster, we measured the responses of wild-type larvae and adults to pure SFAs (14, 16, and 18 carbons) and UFAs (C18 with 1, 2, or 3 double-bonds). Individual and group behavioral tests revealed different preferences in larvae and adults. Larvae preferred UFAs whereas SFAs tended to induce both a strong aversion and a persistent aggregation behavior. Adults generally preferred SFAs, and laid more eggs and had a longer life span when ingesting these substances as compared to UFAs. Our data suggest that insects can discriminate long-chain dietary FAs. The developmental change in preference shown by this species might reflect functional variation in use of FAs or stage-specific nutritional requirements, and may be fundamental for insect use of these major dietary components.
Transient and Permanent Experience with Fatty Acids Changes Drosophila melanogaster Preference and Fitness
Justin Flaven-Pouchon, Thibault Garcia, Dehbia Abed-Vieillard, Jean-Pierre Farine, Jean-Fran?ois Ferveur, Claude Everaerts
PLOS ONE , 2014, DOI: 10.1371/journal.pone.0092352
Abstract: Food and host-preference relies on genetic adaptation and sensory experience. In vertebrates, experience with food-related cues during early development can change adult preference. This is also true in holometabolous insects, which undergo a drastic nervous system remodelling during their complete metamorphosis, but remains uncertain in Drosophila melanogaster. We have conditioned D. melanogaster with oleic (C18:1) and stearic (C18:0) acids, two common dietary fatty acids, respectively preferred by larvae and adult. Wild-type individuals exposed either during a transient period of development–from embryo to adult–or more permanently–during one to ten generation cycles–were affected by such conditioning. In particular, the oviposition preference of females exposed to each fatty acid during larval development was affected without cross-effect indicating the specificity of each substance. Permanent exposure to each fatty acid also drastically changed oviposition preference as well as major fitness traits (development duration, sex-ratio, fecundity, adult lethality). This suggests that D. melanogaster ability to adapt to new food sources is determined by its genetic and sensory plasticity both of which may explain the success of this generalist-diet species.
An Inhibitory Sex Pheromone Tastes Bitter for Drosophila Males
Fabien Lacaille, Makoto Hiroi, Robert Twele, Tsuyoshi Inoshita, Daisuke Umemoto, Gérard Manière, Frédéric Marion-Poll, Mamiko Ozaki, Wittko Francke, Matthew Cobb, Claude Everaerts, Teiichi Tanimura, Jean-Fran?ois Ferveur
PLOS ONE , 2007, DOI: 10.1371/journal.pone.0000661
Abstract: Sexual behavior requires animals to distinguish between the sexes and to respond appropriately to each of them. In Drosophila melanogaster, as in many insects, cuticular hydrocarbons are thought to be involved in sex recognition and in mating behavior, but there is no direct neuronal evidence of their pheromonal effect. Using behavioral and electrophysiological measures of responses to natural and synthetic compounds, we show that Z-7-tricosene, a Drosophila male cuticular hydrocarbon, acts as a sex pheromone and inhibits male-male courtship. These data provide the first direct demonstration that an insect cuticular hydrocarbon is detected as a sex pheromone. Intriguingly, we show that a particular type of gustatory neurons of the labial palps respond both to Z-7-tricosene and to bitter stimuli. Cross-adaptation between Z-7-tricosene and bitter stimuli further indicates that these two very different substances are processed by the same neural pathways. Furthermore, the two substances induced similar behavioral responses both in courtship and feeding tests. We conclude that the inhibitory pheromone tastes bitter to the fly.
Generating Net Forces from Backgrounds of Randomly Created Waves  [PDF]
Claude Gauthier
Journal of Modern Physics (JMP) , 2014, DOI: 10.4236/jmp.2014.516158
Abstract: We examine the possibility of generating net forces on concave isolated objects from backgrounds consisting of randomly created waves carrying momentum. This issue is examined first for waves at the surface of a liquid, and second for quantum vacuum electromagnetic waves, both in relation with a one-side-open rectangular structure whose interior embodies a large number of parallel reflecting plates. Using known results about the Casimir-like effect and the original Casimir effect for parallel plates, we explain why and how such rectangular hollow structures should feel net oriented forces. We briefly describe real systems that would allow testing these theoretical results.
Wave-Particle Duality in Einstein-de Broglie Programs  [PDF]
Claude Elbaz
Journal of Modern Physics (JMP) , 2014, DOI: 10.4236/jmp.2014.518213
Abstract: The standard model of particle physics forms a consistent system for universe description. After following quantum mechanics, it derives particles from relativistic quantum fields. Since it does not include gravitation, it describes only one aspect of the universe. In extension of general relativity, Einstein had proposed a symmetrical and complementary approach of physics. In his program, he privileged a relativist field based on representations for physical phenomena, before a precise mathematical description. It allows completing and unifying the universe description, like both eyes for relief vision, and both ears for stereophonic audition. We propose to show it with many simple examples.
Gravitation and Electromagnetism Conciliated Following Einstein’s Program  [PDF]
Claude Elbaz
Journal of Modern Physics (JMP) , 2015, DOI: 10.4236/jmp.2015.65072
Abstract: The Einstein’s program permits to conciliate gravitation and electromagnetism. Besides the standard model, it forms a consistent system for universe description, founded upon a scalar field propagating at the speed of light c. Matter corresponds to standing waves. Adiabatic variations of frequencies lead to electromagnetic interaction constituted by progressive waves. Classical domain corresponds to geometrical optics approximation, when frequencies are infinitely high, and then hidden. As interactions for matter, Gravitation and Electromagnetism derive from variations of its energy E = mc2. Electromagnetic interaction energy derives from mass variation dE = c2dm, and gravitation from speed of light variation dE = mdc2. Contrarily to gravitation, only electromagnetic interaction serves as a bridge between classical and quantum frames, since it leans directly upon the wave property of matter: its energy dE = hdν = c2dm derives from variations of matter energy E = hν = mc2.
Book Review on Wilsonian Armenia: Stories behind the Failed Project by Rouben Ambartzumian  [PDF]
Claude Mutafian
Open Journal of Social Sciences (JSS) , 2017, DOI: 10.4236/jss.2017.52015
Abstract: The present book deals with a topic which has often been mentioned by various specialists of the Armenian question, but, as far as I know, never been studied per se. Rouben Ambartzumian [below quoted as RA] has decided to dig the question in order to understand and explain why the pro-Armenian projects of US president Woodrow Wilson turned to a total failure. Himself a brilliant world-famous mathematician, RA explores the field scientifically, as thoroughly as possible, in order to find, or eventually to guess, the reasons of the behaviour of the different actors of this tragedy.
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