Contrasting predation services of predator and omnivore diversity mediated by invasive ants in a tropical agroecosystem

Invasive natural enemies are known to either strengthen or weaken the suppression of herbivorous arthropods. However, the impact of invasive species on the predation service provided by natural enemy diversity remains largely unexplored. Here, we tease apart the roles of invasive ants as providers of a predation service and a potential disservice, i.e. reducing the diversity of natural enemies. In mango orchards on Reunion Island, we evaluated the predation service in 20 open fields by simultaneously monitoring the predation on bait eggs and arthropod communities in two strata: the ground surface and the mango tree canopy. Our results show that the predation on bait eggs was limited to the ground surface. This stratum is dominated by three invasive omnivorous ants: Pheidole megacephala and Solenopsis geminata strongly increased the predation rate of bait eggs, whereas Brachymyrmex cordemoyi was responsible for only a small decrease in predation rate. Predation rate was positively related to predator species richness, and was negatively related to omnivore species richness. The negative relationship between the predation rate and omnivore species richness is caused by the most dominant invasive ant, P. megacephala, which reduces omnivore richness and seems to strongly prey on eggs. This study demonstrates, for the first time, the distinct influence of the diversity of two trophic groups on the predation service and how these effects can be mediated by invasive ant species. (Résumé d'auteur

The Cost of Cochlear Implantation: A Review of Methodological Considerations

Objectives. Cost studies can provide useful guidance, so long as they adhere to accepted methodology. Cochlear implants (CIs) are electronic devices introduced surgically into the inner ear. It is a relevant example to review cost study analyses because of its costliness. The aim of this study was to review relevant published cost studies of CI to analyze the method used. Methods. First, we described the key points of cost study methodology. Cost studies relating to CI were systematically reviewed, focussing on an analysis of the different methods used. Results. The methods, data sources, and estimated cost categories in each study varied widely. The paper showed that cost studies adopted significantly different approaches to estimate costs of CI, reflecting a lack of consensus on the methodology of cost studies. Conclusion. To increase its credibility, closer agreement among researchers on the methodological principles of cost studies would be desirable

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tile only ( 1 85-110 dB HL, 250-500 Hz). In the remaining 7 cases, residual hearing was maintained up to at least 6 months after operation with minor changes. Insertion depth angles in these cases ranged from 285 to 420°. For these subjects, the mean preoperative score for words presented at 65 dB SPL was 22%. Mean postoperative scores were 56% for CI alone, and 68% for CI plus ipsilateral hearing aid (p ! 0.05, paired t). For sentences presented in multitalker babble noise at 5 dB SNR, mean scores were 61% CI alone, and 75% CI+IpsiHA (p ! 0.01, paired t). Conclusions: Hearing was conserved during surgery and over time in 70% of conventional candidates implanted with the Nucleus 24 Contour Advance CI who had significant levels of preoperative low-frequency residual hearing ( ^ 60 dB HL). These conventional candidates for CI also benefited from improved speech recognition in noise when using combined ipsilateral electrical and acoustic stimulation

GASCON : Gestion agro-écologique de la santé des cultures et des organismes nuisibles

Le croisement des sciences agronomiques, de l’écologie appliquée à la gestion des agroécosystèmes,et des sciences humaines et sociales, qu’implique la transition agroécologique, pose de nouveaux défis pour répondre aux enjeux agricoles: intégrer des connaissances de différentes disciplines et produites à différentes échelles d’organisation pour agir en situation; développer des cadres d’analyse et démarches intégrant la diversité de situations à gérer par les acteurs et permettant de construire des réponses adaptées à chaque situation; et concevoir et mettre en œuvre des pratiques d’enseignement et d’apprentissage, qui dotent les apprenants de capacités à penser leur action en contexte, en mobilisant des savoirs et savoir-faire multiples en termes de contenus disciplinaires et des savoir-être pour construire des solutions avec une diversité d’acteurs. Dans le champ de la formation, ces défis nécessitent dès lors de revisiter les contenus des enseignements dispensés, les modalités pédagogiques et les dispositifs de formation existants, de manière à appréhender au mieux la complexité des processus à l’œuvre. Pour autant, peu de travaux s’attardent sur les modalités pratiques de ce changement et de ses implications, alors même que de nombreuses initiatives en matière de pédagogie et d’agroécologie se développent ces dernières années. L’objectif de ce séminaire est de promouvoir une information partagée et l’échange d’expériences pour répondre aux enjeux posés par l’agroécologie dans la formation (transversalité, pluridisciplinarité, approche systémique, pédagogies actives). Ces enjeux peuvent se décliner suivant plusieurs entrées : les thématiques enseignées (agriculture, élevage, territoire, alimentation, ...); les pratiques et les dispositifs pédagogiques mis en œuvre pour aborder ces questions (enseignement numérique, dispositifs expérimentaux, projets professionnels, référentiels, ...);les publics d’apprenants: élèves, étudiants, professionnels, ..

Perception of tilt and ocular torsion of vestibular patients during eccentric rotation.

International audienceFour patients following unilateral vestibular loss and four patients complaining of otolith-dependent vertigo were tested during eccentric yaw rotation generating 1 x g centripetal acceleration directed along the interaural axis. Perception of body tilt in roll and in pitch was recorded in darkness using a somatosensory plate that the subjects maintained parallel to the perceived horizon. Ocular torsion was recorded by a video camera. Unilateral vestibular-defective patients underestimated the magnitude of the roll tilt and had a smaller torsion when the centrifugal force was towards the operated ear compared to the intact ear and healthy subjects. Patients with otolithic-dependent vertigo overestimated the magnitude of roll tilt in both directions of eccentric rotation relative to healthy subjects, and their ocular torsion was smaller than in healthy subjects. Eccentric rotation is a promising tool for the evaluation of vestibular dysfunction in patients. Eye torsion and perception of tilt during this stimulation are objective and subjective measurements, which could be used to determine alterations in spatial processing in the CNS

Perception audiovisuelle de la parole chez le sourd postlingual implanté cochléaire et le sujet normo-entendant (étude longitudinale psychophysique et neurofonctionnelle)

TOULOUSE3-BU Sciences (315552104) / SudocSudocFranceF

Auditory recovery and speechreading in cochlear implanted deaf patients : a review

International audienceIn this review, we discuss evidence from our recent studies and the literature that deaf patients after cochlear implantation partly rely on visual cues during auditory recovery and develop mechanisms of audio-visual integration as a strategy to maintain high levels of speech recognition in the noisy auditory environments provided by cochlear implants. This evidence is considered both at the behavioural level and at the level of cortical activity as explored by studies in functional neuroimaging. Since coupling different modalities facilitates perceptual learning in a single modality, we believe that a strong visually and audio-visually based rehabilitation during the first months after cochlear implantation would significantly improve and hasten the functional recovery of speech intelligibility and other auditory functions in these patients

Les maladies connues comme pouvant relever d\textquotesingleun trouble de la régulation pressionnelle intralabyrinthique

International audienc

Mental representation of space in vestibular patients with otolithic or rotatory vertigo.

International audienceIn previous studies, we had observed that the occurrence of geometric illusions was reduced when healthy observers were tilted relative to gravity or placed in microgravity. We hypothesized that the alteration of the gravitational (otolith) input was responsible for this change, presumably because of a connection between vestibular and visual-spatial cognitive functions. In this study, we repeated these experiments in vestibular patients who presented signs of otolith disorders. In agreement with the microgravity data, geometric illusions based on horizontal, vertical, and oblique lines were less frequent in patients with otolithic (nonrotatory) vertigo than in patients with rotatory vertigo and in healthy participants. Other visual illusions not based on perspective were not significantly different across all participant groups. We conclude that the impairment in the processing of gravitational input in the otolithic patients could be at the origin of a deformed mental representation of personal and extrapersonal space