Manioc : Portail | resultats 1 - 20 pour la recherche: Escape behaviour

Éditeur(s) : HAL CCSD Elsevier Masson
Résumé : International audience
The present study tested different sounds that could disturb eagle rays (Aetobatus ocellatus) during their foraging activities at Moorea, French Polynesia. Results showed that artificial white sound and single-frequency tones (40 Hz, 600 Hz or 1 kHz) did not have an effect on rays (at least 90% of rays continued to forage over sand), while playbacks of boat motor sound significantly disturbed rays during foraging activity (60% exhibited an escape behaviour). Overall, our study highlighted the negative effect of boat noises on the foraging activity of eagle rays. These noises produced by boat traffic could, however, have some positive effects for marine aquaculture if they could be used as a deterrent to repel the eagle rays, main predators of the pearl oysters.
Notre étude teste différents types de sons qui pourraient perturber les raies-aigles (Aetobatus ocellatus) pendant leur prise de nourriture dans le lagon de Moorea, en Polynésie française. Les résultats montrent que le bruit artificiel blanc ou des fréquences uniques (40 Hz, 600 Hz ou 1 kHz) n’ont aucun effet sur les raies (au moins 90 % des raies continuent de se nourrir dans le sable), tandis que l’enregistrement d’un moteur de bateau les perturbe significativement dans cette activité (60 % des individus ont un comportement de fuite). Notre étude met ainsi en évidence l’effet négatif des bruits anthropogéniques sur les activités de nourrissage des raies-aigles. Ces bruits produits par les bateaux pourraient néanmoins avoir un effet positif pour l’aquaculture marine s’ils pouvaient être utilisés comme répulsifs des raies, principaux prédateurs de l’huître perlière.
ISSN: 1631-0691

Droits : http://creativecommons.org/licenses/by-nc-nd/
hal-01297683
https://hal-univ-perp.archives-ouvertes.fr/hal-01297683
https://hal-univ-perp.archives-ouvertes.fr/hal-01297683/document
https://hal-univ-perp.archives-ouvertes.fr/hal-01297683/file/1-s2.0-S1631069116000020-main.pdf
DOI : 10.1016/j.crvi.2016.01.001

| Plus

Negro slavery, or A view of some of the more prominent features of that state of society, as it exists in the United States of America and in the colonies of the West Indies, especially in Jamaica
Année de publication :

| Plus

Antigua and the Antiguans: a full account of the colony and its inhabitants from the time of the Caribs to the present day, interspersed with anecdotes and legends : also, an impartial view of slavery and the free labour systems, the statistics of the island, and biographical notices of the principal families, Volume 2
Année de publication :

| Plus

Six months in the West Indies
Auteur(s) : Coleridge, Henry Nelson (1798-1843)
Année de publication :

| Plus

Secret anecdotes of the revolution of the 18th fructidor ; september 4th, 1797 ; and new memoirs of the persons deported to Guiana, written by themselves : containing Letters from Général Murinais, Messrs. Barthélemy, Tronçon-du-Coudray, Laffond-Ladébat, De la Rue, &c. &c... ; A Narrative of events that took place at Guiana subsequent to the escape of Pichegru, Ramel, &c. ; A Picture of the prisons of Rochefort, by Richer-Serisy ; An Authentic account of the captivity and escape of Sir Sydney Smith ; A Memoire by Barbé-Marbois, &c. &c. ; Forming a sequel to the "Narrative of General Ramel"
Année de publication :

| Plus

Reports from committees : eighteen volumes. Sugar and coffee planting. Session 18 november 1847 - 5 september 1848. Part. 1
Auteur(s) : Grande Bretagne. House of commons. Library
Année de publication :

| Plus

The West Indies in 1837; being the journal of a visit to Antigua, Montserrat, Dominica, St. Lucia, Barbados, and Jamaïca : undertaken for the purpose of ascertaining the actual condition of the negro population of those islands
Auteur(s) : Sturge, Joseph (1793-1859) Harvey, Thomas (1812-1884)
Année de publication :

| Plus

Hayti or the black republic
Auteur(s) : Saint-John, Spenser Buckingham (1825-1910 ; Sir)
Année de publication :

| Plus

Upper mantle flow beneath and around the Hangay Dome, central Mongolia
Auteur(s) : Barruol, Guilhem Deschamps, Anne Déverchère, Jacques Mordvinova, Valentina V. Munkhuu, Ulziibat Perrot, Julie Artemiev, A. Dugarmaa, T.
Auteurs secondaires : Géosciences Montpellier ; Université des Antilles et de la Guyane (UAG) - Institut national des sciences de l'Univers (INSU - CNRS) - Université de Montpellier (UM) - Centre National de la Recherche Scientifique (CNRS) Géoazur (GEOAZUR) ; Université Pierre et Marie Curie - Paris 6 (UPMC) - Université Nice Sophia Antipolis (UNS) ; Université Côte d'Azur (UCA) - Université Côte d'Azur (UCA) - Institut national des sciences de l'Univers (INSU - CNRS) - Observatoire de la Côte d'Azur - Centre National de la Recherche Scientifique (CNRS) Université européenne de Bretagne (UEB) Domaines Océaniques (LDO) ; Centre National de la Recherche Scientifique (CNRS) - Institut d'écologie et environnement - Observatoire des Sciences de l'Univers - Université de Brest (UBO) - Institut national des sciences de l'Univers (INSU - CNRS) Institute of the Earth's crust ; Siberian Branch of the Russian Academy of Sciences (SB RAS) Research Center of Astronomy and Geophysics of the Mongolian Academy of Science

Éditeur(s) : HAL CCSD Elsevier
Résumé : International audience
Mongolia represents the northernmost area affected by the India–Asia collision, and it is actively deformed along transpressive belts closely associated with large-scale strike-slip faults. The active and past mantle flow beneath this region is, however, poorly known. In order to investigate deep mantle deformation beneath central Mongolia and its relation with the surrounding major structures such as the Siberian craton, the Gobi–Altay belt and the Baikal rift, a NS-trending profile of broadband seismic stations has been deployed in the summer 2003 from the southern Siberian craton to the Gobi–Altay range, crossing the entire Hangay dome. Mantle flow is deduced from the splitting of teleseismic shear waves such as SKS phases. In eastern Mongolia, the permanent station ULN in Ulaanbaatar reveals the presence of two anisotropic layers, the upper one being oriented NE–SW, close to the trend of lithospheric structures and the lower one NW–SE, close to the trend of Eurasia absolute plate motion. Along the NS profile in central Mongolia, seismic anisotropy deduced from SKS splitting reveals a homogeneous NW–SE trending structure, fully consistent with the observations made in the Altay–Sayan in western Mongolia. The observed delay times of 1.5 to more than 2.0 s favor consistent mantle flow over large mantle thicknesses. Since the lithosphere is less than 100 km thick beneath central Mongolia and since the observed fast directions are parallel to the trend of the lithospheric structures but also close to the trend of the absolute plate motion, we propose that both the lithosphere and the asthenosphere may join their anisotropic effects beneath central Mongolia to explain the large delay times. Although GPS vectors represent the instantaneous displacement of the Earth's surface and SKS splitting the time and vertical integration of finite strain at depth, we use the opportunity of the dense geodetic measurements available in this region to discuss the anisotropy pattern in term of present-day deformation. In the Eurasia-fixed reference frame, GPS and SKS both depict a similar trend beneath central Mongolia, suggesting a lithospheric block “escaping” toward the east that could orient olivine a-axes in the upper mantle, within a transpressive tectonic regime. A different behaviour is observed in western Mongolia: the GPS vectors trend NS, close to the regional compression direction, whereas the fast SKS directions trend EW, suggesting a tectonic regime close to a mode of axial shortening, generating the development of an EW-trending foliation at depth. We therefore propose that Mongolia is a place where active and frozen lithospheric deformation may add their effects, together with the sublithospheric flow. In the three sources of anisotropy inferred, a fundamental role is played by the Siberian craton that acted as an undeformable core of the continent through time: the frozen Paleozoic and Mesozoic structures wrap around the craton, building up the fast anisotropic direction pattern; the present-day sublithospheric flow induced by the plate motion is likely deflecting around its deep roots; finally, the present-day tectonic regime appears to be controlled by the presence of the craton to the north.
ISSN: 0012-821X

hal-00407853
https://hal.archives-ouvertes.fr/hal-00407853
https://hal.archives-ouvertes.fr/hal-00407853/document
https://hal.archives-ouvertes.fr/hal-00407853/file/Barruol_SKS_Mongolia_EPSL2008_hal.pdf
DOI : 10.1016/j.epsl.2008.07.027

| Plus