Liens entre les fonctions exécutives et les manifestations psychopathologiques chez des enfants d'âge scolaire ayant une déficience intellectuelle

Plusieurs études ont démontré que les enfants ayant une déficience intellectuelle (DI) sont plus à risque de présenter des manifestations psychopathologiques que ceux au développement typique. Différentes hypothèses ont été avancées pour expliquer cette plus forte prévalence. L'hypothèse biologique présente un intérêt particulier puisque des anomalies cérébrales sont fréquemment répertoriées chez les personnes présentant une DI. De façon plus particulière, le développement des fonctions executives pourrait être altéré ou survenir plus tardivement chez ces dernières. Puisque des liens ont été retrouvés entre des déficits exécutifs et des manifestations psychopathologiques dans le contexte de troubles du développement, il apparaît pertinent de s'intéresser aux liens entre les fonctions executives et les manifestations psychopathologiques dans le domaine de la DI. De plus, des liens ont été trouvés entre les manifestations psychopathologiques et le sexe, le Qï et l'âge de l'enfant, mais la direction de ces liens varient selon les écrits. Ces éléments doivent être pris en considération, car ils sont susceptibles d'intervenir dans les relations entre les fonctions executives et les manifestations psychopathologiques. Cette étude vise donc l'étude du lien entre les fonctions executives et les manifestations psychopathologiques chez des enfants d'âge scolaire ayant une DI en tenant compte du sexe, de l'âge et du QI. L'échantillon est composé de 122 enfants de 5 à 21 ans présentant une DI (54 filles et 68 garçons). Leurs parents ont évalué leurs manifestations psychopathologiques et leur fonctionnement exécutif à l'aide du Developmental Behaviour Checklist ? Second Edition ? Primary Carer Version (DBC-P) et du Behavior Rating Inventory of Executive Function (BRIEF) respectivement. Les résultats indiquent que les filles présentent un plus haut niveau d'anxiété que les garçons et plus de difficultés sur le plan du contrôle émotionnel. De plus, la métacognition, qui fait référence à la capacité de l'enfant à gérer ses comportements et qui regroupe l'initiation, la mémoire de travail, la planification, l'organisation du matériel et l'autoévaluation, a été identifiée comme jouant un rôle médiateur dans la relation entre l'âge et les comportements centrés sur soi et un rôle de suppression dans la relation entre l'âge et les problèmes relationnels. Aucun lien significatif n'est constaté entre le QI et les fonctions executives. Ces résultats mettent en lumière l'importance de considérer le développement des fonctions executives, plus particulièrement celui de la métacognition, pour expliquer la diminution des comportements centrés sur soi lorsque l'enfant vieillit. À l'inverse, son développement contribue à l'augmentation des problèmes relationnels, car l'enfant devient alors davantage conscient de ses capacités, de ses limitations et de son entourage. Il devient alors important de développer des interventions qui permettront le développement de la métacognition chez l'enfant ayant une DI et des interventions qui permettront de l'outiller pour faire face à ces prises de conscience. Il serait également intéressant d'étudier plus en détail la plus forte prévalence d'anxiété chez les filles et d'étudier si les difficultés de contrôle émotionnel constatées par les parents pourraient y être liées. Enfin, le fait que le QI ne soit pas lié aux fonctions executives chez les enfants ayant une DI soulève la possibilité d'une relation non linéaire entre ces deux éléments qui pourrait être clarifiée par des études futures

Migrant Semipalmated Sandpipers (Calidris pusilla) Have Over Four Decades Steadily Shifted Towards Safer Stopover Locations

Peregrine falcons (Falco peregrinus) have undergone a steady hemisphere-wide recovery since the ban on DDT in 1973, resulting in an ongoing increase in the level of danger posed for migrant birds, such as Arctic-breeding sandpipers. We anticipate that in response migrant semipalmated sandpipers (Calidris pusilla) have adjusted migratory behavior, including a shift in stopover site usage toward locations offering greater safety from falcon predation. We assessed semipalmated sandpiper stopover usage within the Atlantic Canada Shorebird Survey dataset. Based on 3,030 surveys (totalling ~32M birds) made during southward migration, 1974–2017, at 198 stopover locations, we assessed the spatial distribution of site usage in each year (with a “priority matching distribution” index, PMD) in relation to the size (intertidal area) and safety (proportion of a site\u27s intertidal area further than 150 m of the shoreline) of each location. The PMD index value is >1 when usage is concentrated at dangerous locations, 1.0 when usage matches location size, and <1 when usage is concentrated at safer locations. A large majority of migrants were found at the safest sites in all years, however our analysis of the PMD demonstrated that the fraction using safer sites increased over time. In 1974, 80% of birds were found at the safest 20% of the sites, while in 2017, this had increased to 97%. A sensitivity analysis shows that the shift was made specifically toward safer (and not just larger) sites. The shift as measured by a PMD index decline cannot be accounted for by possible biases inherent in the data set. We conclude that the data support the prediction that increasing predator danger has induced a shift by southbound migrant semipalmated sandpipers to safer sites

A complex speciation-richness relationship in a simple neutral model

Speciation is the "elephant in the room" of community ecology. As the ultimate source of biodiversity, its integration in ecology's theoretical corpus is necessary to understand community assembly. Yet, speciation is often completely ignored or stripped of its spatial dimension. Recent approaches based on network theory have allowed ecologists to effectively model complex landscapes. In this study, we use this framework to model allopatric and parapatric speciation in networks of communities and focus on the relationship between speciation, richness, and the spatial structure of communities. We find a strong opposition between speciation and local richness, with speciation being more common in isolated communities and local richness being higher in more connected communities. Unlike previous models, we also find a transition to a positive relationship between speciation and local richness when dispersal is low and the number of communities is small. Also, we use several measures of centrality to characterize the effect of network structure on diversity. The degree, the simplest measure of centrality, is found to be the best predictor of local richness and speciation, although it loses some of its predictive power as connectivity grows. Our framework shows how a simple neutral model can be combined with network theory to reveal complex relationships between speciation, richness, and the spatial organization of populations.Comment: 9 pages, 5 figures, 1 table, 50 reference

Toward food sovereignty for coastal communities of eastern Québec : co-designing a website to support consumption of edible resources from the St. Lawrence River, Estuary, and Gulf

Background. Despite the abundance and proximity of edible marine resources, coastal communities along the St. Lawrence in Eastern Québec rarely consume these resources. Within a community-based food sovereignty project, Manger notre Saint-Laurent (‘‘Sustenance from our St. Lawrence''), members of participating communities (3 nonIndigenous, 1 Indigenous) identified a need for a web-based decision tool to help make informed consumption choices. Methods. We thus aimed to co-design a prototype website that facilitates informed choices about consuming local edible marine resources based on seasonal and regional availability, food safety, nutrition, and sustainability, with community members, regional stakeholders, and experts in user experience design and web development. We conducted 48 interviews with a variety of people over 3 iterative cycles, assessing the prototype's ease of use with a validated measure, the System Usability Scale. Results. Community members, regional stakeholders, and other experts identified problematic elements in initial versions of the website (e.g., confusing symbols). We resolved issues and added features people identified as useful. Usability scores reached ‘‘best imaginable'' for both the second and the third versions and did not differ significantly between sociodemographic groups. The final prototype includes a tool to explore each species and index cards to regroup accurate evidence relevant to each species. Conclusions. Engaging co-designers with different sociodemographic characteristics brought together a variety of perspectives. Several components would not have been included without co-designers' input; other components were greatly improved thanks to their feedback. Co-design approaches in research and intervention development are preferable to foster the inclusion of a variety of people. Once the prototype is programmed and available online, we hope to evaluate the website to determine its effects on food choices

Morning and Evening-Type Differences in Slow Waves during NREM Sleep Reveal Both Trait and State-Dependent Phenotypes

Brain recovery after prolonged wakefulness is characterized by increased density, amplitude and slope of slow waves (SW, <4 Hz) during non-rapid eye movement (NREM) sleep. These SW comprise a negative phase, during which cortical neurons are mostly silent, and a positive phase, in which most neurons fire intensively. Previous work showed, using EEG spectral analysis as an index of cortical synchrony, that Morning-types (M-types) present faster dynamics of sleep pressure than Evening-types (E-types). We thus hypothesized that single SW properties will also show larger changes in M-types than in E-types in response to increased sleep pressure. SW density (number per minute) and characteristics (amplitude, slope between negative and positive peaks, frequency and duration of negative and positive phases) were compared between chronotypes for a baseline sleep episode (BL) and for recovery sleep (REC) after two nights of sleep fragmentation. While SW density did not differ between chronotypes, M-types showed higher SW amplitude and steeper slope than E-types, especially during REC. SW properties were also averaged for 3 NREM sleep periods selected for their decreasing level of sleep pressure (first cycle of REC [REC1], first cycle of BL [BL1] and fourth cycle of BL [BL4]). Slope was significantly steeper in M-types than in E-types in REC1 and BL1. SW frequency was consistently higher and duration of positive and negative phases constantly shorter in M-types than in E-types. Our data reveal that specific properties of cortical synchrony during sleep differ between M-types and E-types, although chronotypes show a similar capacity to generate SW. These differences may involve 1) stable trait characteristics independent of sleep pressure (i.e., frequency and durations) likely linked to the length of silent and burst-firing phases of individual neurons, and 2) specific responses to increased sleep pressure (i.e., slope and amplitude) expected to depend on the synchrony between neurons

Membrane-Associated RING-CH Proteins Associate with Bap31 and Target CD81 and CD44 to Lysosomes

Membrane-associated RING-CH (MARCH) proteins represent a family of transmembrane ubiquitin ligases modulating intracellular trafficking and turnover of transmembrane protein targets. While homologous proteins encoded by gamma-2 herpesviruses and leporipoxviruses have been studied extensively, limited information is available regarding the physiological targets of cellular MARCH proteins. To identify host cell proteins targeted by the human MARCH-VIII ubiquitin ligase we used stable isotope labeling of amino-acids in cell culture (SILAC) to monitor MARCH-dependent changes in the membrane proteomes of human fibroblasts. Unexpectedly, we observed that MARCH-VIII reduced the surface expression of Bap31, a chaperone that predominantly resides in the endoplasmic reticulum (ER). We demonstrate that Bap31 associates with the transmembrane domains of several MARCH proteins and controls intracellular transport of MARCH proteins. In addition, we observed that MARCH-VIII reduced the surface expression of the hyaluronic acid-receptor CD44 and both MARCH-VIII and MARCH-IV sequestered the tetraspanin CD81 in endo-lysosomal vesicles. Moreover, gene knockdown of MARCH-IV increased surface levels of endogenous CD81 suggesting a constitutive involvement of this family of ubiquitin ligases in the turnover of tetraspanins. Our data thus suggest a role of MARCH-VIII and MARCH-IV in the regulated turnover of CD81 and CD44, two ubiquitously expressed, multifunctional proteins

Long-Term Continental Changes in Wing Length, but Not Bill Length, of a Long-Distance Migratory Shorebird

We compiled a &gt;50‐year record of morphometrics for semipalmated sandpipers (Calidris pusilla), a shorebird species with a Nearctic breeding distribution and intercontinental migration to South America. Our data included &gt;57,000 individuals captured 1972–2015 at five breeding locations and three major stopover sites, plus 139 museum specimens collected in earlier decades. Wing length increased by ca. 1.5 mm (&gt;1%) prior to 1980, followed by a decrease of 3.85 mm (nearly 4%) over the subsequent 35 years. This can account for previously reported changes in metrics at a migratory stopover site from 1985 to 2006. Wing length decreased at a rate of 1,098 darwins, or 0.176 haldanes, within the ranges of other field studies of phenotypic change. Bill length, in contrast, showed no consistent change over the full period of our study. Decreased body size as a universal response of animal populations to climate warming, and several other potential mechanisms, are unable to account for the increasing and decreasing wing length pattern observed. We propose that the post‐WWII near‐extirpation of falcon populations and their post‐1973 recovery driven by the widespread use and subsequent limitation on DDT in North America selected initially for greater flight efficiency and latterly for greater agility. This predation danger hypothesis accounts for many features of the morphometric data and deserves further investigation in this and other species

Long-distance migratory shorebirds travel faster towards their breeding grounds, but fly faster post-breeding

Long-distance migrants are assumed to be more time-limited during the pre-breeding season compared to the post-breeding season. Although breeding-related time constraints may be absent post-breeding, additional factors such as predation risk could lead to time constraints that were previously underestimated. By using an automated radio telemetry system, we compared pre- and post-breeding movements of long-distance migrant shorebirds on a continent-wide scale. From 2014 to 2016, we deployed radio transmitters on 1,937 individuals of 4 shorebird species at 13 sites distributed across North America. Following theoretical predictions, all species migrated faster during the pre-breeding season, compared to the post-breeding season. These differences in migration speed between seasons were attributable primarily to longer stopover durations in the post-breeding season. In contrast, and counter to our expectations, all species had higher airspeeds during the post-breeding season, even after accounting for seasonal differences in wind. Arriving at the breeding grounds in good body condition is beneficial for survival and reproductive success and this energetic constraint might explain why airspeeds are not maximised in the pre-breeding season. We show that the higher airspeeds in the post-breeding season precede a wave of avian predators, which could suggest that migrant shorebirds show predation-minimizing behaviour during the post-breeding season. Our results reaffirm the important role of time constraints during northward migration and suggest that both energy and predation-risk constrain migratory behaviour during the post-breeding season