Foraging Responses of Black-Legged Kittiwakes to Prolonged Food-Shortages around Colonies on the Bering Sea Shelf

We hypothesized that changes in southeastern Bering Sea foraging conditions for black-legged kittiwakes (Rissa tridactyla) have caused shifts in habitat use with direct implications for population trends. To test this, we compared at-sea distribution, breeding performance, and nutritional stress of kittiwakes in three years (2008–2010) at two sites in the Pribilof Islands, where the population has either declined (St. Paul) or remained stable (St. George). Foraging conditions were assessed from changes in (1) bird diets, (2) the biomass and distribution of juvenile pollock (Theragra chalcogramma) in 2008 and 2009, and (3) eddy kinetic energy (EKE; considered to be a proxy for oceanic prey availability). In years when biomass of juvenile pollock was low and patchily distributed in shelf regions, kittiwake diets included little or no neritic prey and a much higher occurrence of oceanic prey (e.g. myctophids). Birds from both islands foraged on the nearby shelves, or made substantially longer-distance trips overnight to the basin. Here, feeding was more nocturnal and crepuscular than on the shelf, and often occurred near anticyclonic, or inside cyclonic eddies. As expected from colony location, birds from St. Paul used neritic waters more frequently, whereas birds from St. George typically foraged in oceanic waters. Despite these distinctive foraging patterns, there were no significant differences between colonies in chick feeding rates or fledging success. High EKE in 2010 coincided with a 63% increase in use of the basin by birds from St. Paul compared with 2008 when EKE was low. Nonetheless, adult nutritional stress, which was relatively high across years at both colonies, peaked in birds from St. Paul in 2010. Diminishing food resources in nearby shelf habitats may have contributed to kittiwake population declines at St Paul, possibly driven by increased adult mortality or breeding desertion due to high foraging effort and nutritional stress

La perception musicale chez le patient sourd implanté cochléaire (intérêts de l'audition résiduelle)

TOULOUSE3-BU Santé-Centrale (315552105) / SudocSudocFranceF

L'immunité des plantes : pour des cultures résistantes aux maladies

Les plantes disposent d'une immunité naturelle qui leur permet de résister aux maladies et aux agressions parasitaires dans leur environnement. L'invention puis le développement de l'agriculture ont cependant créé des milieux très favorables à l'émergence de nouvelles maladies et au développement des épidémies. Cette vulnérabilité sanitaire s'est ensuite accentuée avec l'intensification agricole, à partir des années 1950, de sorte que le recours généralisé aux pesticides de synthèse est devenu un pilier essentiel de la production. Ce modèle est désormais remis en cause et le développement d'une protection agroécologique des cultures devient une nécessité. Comprendre comment fonctionne l'immunité des plantes et déchiffrer leur arsenal de défense face aux agressions parasitaires est essentiel pour produire des variétés résistantes et réduire la dépendance de l'agriculture à la protection chimique. Mais il faut compter avec la formidable capacité d'adaptation des populations pathogènes, qui conduit les chercheurs à imaginer des stratégies complexes pour maintenir efficace la résistance des variétés cultivées. Les gènes qui confèrent la résistance aux plantes commencent à être perçus comme un bien commun à préserver absolument. Cet ouvrage explicite les concepts fondamentaux et s'appuie sur des études de cas pour réaliser une synthèse très complète des travaux en biologie, en modélisation et en sciences sociales sur ce qu'est l'immunité végétale et sur la manière dont elle pourrait concourir à une agriculture respectueuse de l'environnement

Foraging responses of black-legged kittiwakes to prolonged food-shortages around colonies on the Bering Sea Shelf

We hypothesized that changes in southeastern Bering Sea foraging conditions for black-legged kittiwakes (Rissa tridactyla) have caused shifts in habitat use with direct implications for population trends. To test this, we compared at-sea distribution, breeding performance, and nutritional stress of kittiwakes in three years (2008–2010) at two sites in the Pribilof Islands, where the population has either declined (St. Paul) or remained stable (St. George). Foraging conditions were assessed from changes in (1) bird diets, (2) the biomass and distribution of juvenile pollock (Theragra chalcogramma) in 2008 and 2009, and (3) eddy kinetic energy (EKE; considered to be a proxy for oceanic prey availability). In years when biomass of juvenile pollock was low and patchily distributed in shelf regions, kittiwake diets included little or no neritic prey and a much higher occurrence of oceanic prey (e.g. myctophids). Birds from both islands foraged on the nearby shelves, or made substantially longer-distance trips overnight to the basin. Here, feeding was more nocturnal and crepuscular than on the shelf, and often occurred near anticyclonic, or inside cyclonic eddies. As expected from colony location, birds from St. Paul used neritic waters more frequently, whereas birds from St. George typically foraged in oceanic waters. Despite these distinctive foraging patterns, there were no significant differences between colonies in chick feeding rates or fledging success. High EKE in 2010 coincided with a 63% increase in use of the basin by birds from St. Paul compared with 2008 when EKE was low. Nonetheless, adult nutritional stress, which was relatively high across years at both colonies, peaked in birds from St. Paul in 2010. Diminishing food resources in nearby shelf habitats may have contributed to kittiwake population declines at St Paul, possibly driven by increased adult mortality or breeding desertion due to high foraging effort and nutritional stress

Categorization of common sounds by cochlear implanted and normal hearing adults

International audienceAuditory categorization involves grouping of acoustic events along one or more shared perceptual di- mensions which can relate to both semantic and physical attributes. This process involves both high level cognitive processes (categorization) and low-level perceptual encoding of the acoustic signal, both of which are affected by the use of a cochlear implant (CI) device. The goal of this study was twofold: I) compare the categorization strategies of CI users and normal hearing listeners (NHL) II) investigate if any characteristics of the raw acoustic signal could explain the results. 16 experienced CI users and 20 NHL were tested using a Free-Sorting Task of 16 common sounds divided into 3 predefined categories of environmental, musical and vocal sounds. Multiple Correspondence Analysis (MCA) and Hierarchical Clustering based on Principal Components (HCPC) show that CI users followed a similar categorization strategy to that of NHL and were able to discriminate between the three different types of sounds. However results for CI users were more varied and showed less inter-participant agreement. Acoustic analysis also highlighted the average pitch salience and average autocorrelation peak as being important for the perception and categorization of the sounds. The results therefore show that on a broad level of categorization CI users may not have as many difficulties as previously thought in discriminating certain kinds of sound; however the perception of individual sounds remains challenging

Reaction time data for monkey 1 (A), for monkey 2 (B) and for humans (C).

<p>Blue box plots correspond to auditory (A), green to visual (V) and red to auditory—visual (AV) stimuli. The box and horizontal bar within represent the interquartile range and the median of RT, respectively. The whiskers extend to the most extreme data point, which is no more than 1.5 times the interquartile range from the box. The notch approximates a 95% confidence interval for the median. Significance is reported using asterisks depending on the P value: * for p<0.05, ** for p<0.01 and *** for p<0.001.</p

Formula of physical parameters of sounds and images.

<p>Formula of physical parameters of sounds and images.</p

Percentage of normalized reaction time for different combinations of successive modalities.

<p>Auditory (A) N trials are plotted in the left part of the figures, visual (V) in the center and auditory-visual (AV) in the right part. N trials are sorted by N-1 trials’ modality, with auditory on the left in blue, visual in the center in green and auditory-visual on the right in red. Once sorted, N-1 reaction times are divided by the median reaction time of all N trials for the corresponding modality. For example, for the three leftmost bars, the data was normalized by dividing by the median reaction time of all auditory trials. Bars and error bars represent respectively median and 95% confidence interval of the median. Significance is reported using asterisks depending on the P value: * for p<0.05, ** for p<0.01 and *** for p<0.001.</p

Multisensory gain for each stimulus, ranked by gain, for the 3 subject species.

<p>Group 1 (orange) corresponds to stimuli which induce positive gain and race model violation, group 2 (yellow) to stimuli which induce positive gain and satisfy race model, group 3 (light grey) to stimuli which induce positive gain and violate the race model inversely and group 4 (dark grey) to stimuli with negative gain and violate the race model inversely.</p

Effect of congruence (upper part) and salience (lower part) on multisensory gains.

<p>Same convention as in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0172480#pone.0172480.g001" target="_blank">Fig 1</a> for the box plots. Significance is reported using asterisks depending on the P value: * for p<0.05, ** for p<0.01 and *** for p<0.001.</p