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La Grande Muraille Verte en tant qu’imaginaire socio-technique
No full textAvril 2024L'Institute of Development Studies (IDS) produit une recherche de renommée mondiale, qui contribue à transformer les savoirs, les actions et les directions en vue d'un développement mondial plus équitable pour les générations à venir.</div
Citoyenneté et éducation : quelle éthique de la participation des enfants ?
No full textInternational audienceAccéder aux expériences citoyennes des enfants et des adolescents dans les contextes éducatifs constitue un enjeu majeur des recherches actuelles sur la construction des rapports à la citoyenneté dans l’enfance et à l’adolescence. A l’aune de la Convention Internationale des Droits de l’Enfant (CIDE, 1989) et de la conception de la citoyenneté développée par Chombart-de-Lauwe (1990), cet article examine les enjeux épistémologiques et méthodologiques liés à la prise en compte des points de vue des enfants, en particulier pour mieux comprendre l’exercice de la citoyenneté et penser le positionnement des adultes dans les contextes éducatifs. Les auteurs discutent ensuite des enjeux éthiques et psychologiques liés à la participation des enfants, au regard des nombreux paradoxes qui subsistent aujourd’hui concernant l’évolution du statut de l’enfant-citoyen, sa place dans la société et dans la recherche et l’exercice de ses droits de participation
Citizenship Education in Childhood: French Children’s and Adults’ Views on the Experiences of Children Elected to a Children’s Municipal Council
No full textInternational audienceFrom a psychosocial and developmental perspective with regard to the construction of citizenship, this study focused on the experiences of French school-age children elected to a children’s municipal council (CMC). The CMC, citizenship education program, is an instance of participatory democracy in which children (age 9–10) are elected by their peers for a two-year term. We examined the experiences of these children in the CMC, taking both their points of view and those of the CMC’s adult promoters into consideration. Taking an exploratory qualitative approach, we conducted interviews with 19 elected children and 5 adults (the 2 elected representatives in charge of children and education, the head of the children’s department, the technical advisor to the city’s CMC, and the head of the Popular Education Association in charge of running the CMC). Thematic analysis of children’s and adults’ discourse showed many inter- and intra-individual variabilities in their points of view. These results highlight the importance of considering children’s perspectives on their experiences of participatory democracy, and of studying the construction of citizenship in relation to children’s development
Population genomics of the rice landrace Acuce reveals exceptional dynamics of immune receptors
No full textInternational audienceLandraces are important resources for breeding programs. However, the diversity harbored at the genomic level by landraces is yet to be analyzed. Here we sequenced more than 200 individual plants from the long-lasting and durably resistant rice landrace Acuce (Oryza sativa subsp. indica). We found that Acuce exhibits diversity levels as high as 38% of the entire indica sub-species. We pinpoint signatures of selection in favor of polymorphism associated with resistance, but not other agronomic trait genes. Furthermore, we provide evidences that emerging properties upon mixing genomic diversity also increase Acuce's performances
Cardiopulmonary Fitness and Physical Activity Among Children and Adolescents With Inherited Cardiac Disease
No full textInternational audienceImportance: Historical restrictions on children with inherited cardiac arrhythmia or cardiomyopathy have been implemented to mitigate the potential risk of sudden death, but these limitations can be detrimental to overall health and cardiopulmonary fitness.Objectives: To evaluate cardiopulmonary fitness and physical activity among children with inherited cardiac disease and identify the factors associated with maximum oxygen uptake (V̇o2max) in this population.Design, Setting, and Participants: This cross-sectional, multicenter, prospective controlled study was conducted in 7 tertiary care expert centers for inherited cardiac disease in France from February 1, 2021, to June 20, 2023, with a 2-week follow-up. Participants included 100 children and adolescents aged 6 to 17 years with inherited cardiac arrhythmia or cardiomyopathy who were compared with 107 sex- and age-matched controls.Main Outcomes and Measures: Maximum oxygen uptake was assessed using cardiopulmonary exercise testing, and results were expressed using pediatric reference z score values. The main determinants of V̇o2max included clinical (New York Heart Association [NYHA] functional class, treatment, echocardiographic, and electrocardiogram variables), functional (cardiopulmonary exercise test parameters), sociodemographic (sex, schooling, and parents’ education), and behavioral (physical activity and motivation) characteristics.Results A total of 100 patients (mean [SD] age, 12.7 [3.1] years; 52 boys [52.0%]) and 107 controls (mean [SD] age, 11.7 [3.3] years; 54 boys [50.5%]) were included. The V̇o2max was lower in patients than controls, expressed as z scores (mean [SD] score, −1.49 [1.48] vs −0.16 [0.97]; P < .001) or raw values (mean [SD] value, 32.2 [7.9] vs 40.2 [8.5] mL/kg/min; P < .001). Moderate to vigorous physical activity levels were lower in patients than in controls (mean [SD] level, 42.0 [23.6] vs 48.2 [20.4] min/d; P = .009). The final multivariable model explained 80% of the V̇o2max by integrating clinical (lower NYHA functional class, absence of ventricular dilatation, and absence of implantable cardioverter-defibrillator), functional (higher forced vital capacity and ventilatory anaerobic threshold), sociodemographic (male sex, normal progression of schooling, and higher maternal educational level), and behavioral (higher self-reported physical activity and motivation toward physical activity) parameters.Conclusions and Relevance: This cross-sectional study suggests that levels of cardiopulmonary fitness and physical activity were lower in children and adolescents with inherited cardiac disease than in healthy controls, even after adjusting for use of β-blockers and using modern pediatric reference models. Assessing cardiopulmonary fitness among children with inherited cardiac disease can contribute to engaging in a shared decision-making process for sports participation and preventive interventions, such as early cardiac rehabilitation programs
Association between herpes simplex virus infection and Alzheimer's disease biomarkers: analysis within the MAPT trial.
No full textInternational audienceIn vitro and animal studies have suggested that inoculation with herpes simplex virus 1 (HSV-1) can lead to amyloid deposits, hyperphosphorylation of tau, and/or neuronal loss. Here, we studied the association between HSV-1 and Alzheimer's disease biomarkers in humans. Our sample included 182 participants at risk of cognitive decline from the Multidomain Alzheimer Preventive Trial who had HSV-1 plasma serology and an amyloid PET scan. Plasma Aβ42/40 ratio, neurofilament light chain and p-tau181 were also available for a sub-sample of participants. Multivariate linear regressions were performed and stratified by APOE4 genotype. The median age was 74.0 years, 85.2% were infected with HSV-1. Infected participants tended to have a lower cortical amyloid load than uninfected participants (β = -0.08, p = 0.06), especially those suspected of reactivating HSV-1 most frequently (i.e. with a high anti-HSV-1 IgG level; n = 58, β = -0.09 p = 0.04). After stratification, the association was only significant in APOE4 carriers (n = 43, β = -0.21 p = 0.01). No association was found with the plasma biomarkers. The trend toward lower cortical amyloid load in HSV-1-infected participants was unexpected given the pre-existing literature and may be explained either by a modified immune response in HSV-1 infected subjects which could favour the clearance of amyloid deposits or by a selection bias
Gradient correlation is a key ingredient to accelerate SGD with momentum
No full textInternational audienceEmpirically, it has been observed that adding momentum to Stochastic Gradient Descent (SGD) accelerates the convergence of the algorithm. However, the literature has been rather pessimistic, even in the case of convex functions, about the possibility of theoretically proving this observation. We investigate the possibility of obtaining accelerated convergence of the Stochastic Nesterov Accelerated Gradient (SNAG), a momentum-based version of SGD, when minimizing a sum of functions in a convex setting. We demonstrate that the average correlation between gradients allows to verify the strong growth condition, which is the key ingredient to obtain acceleration with SNAG. Numerical experiments, both in linear regression and deep neural network optimization, confirm in practice our theoretical results
Imaginaires et ambiguïtés : l'institutionnalisation des pratiques informelles des bergers dans les plantations forestières du plateau de Millevaches
No full textInternational audienceSur le plateau de Millevaches, les imaginaires liés à la forêt se confrontent à ceux, totalement autres, de « la reconquête pastorale » (Morsel, 2021) des paysages ouverts de landes et de tourbières. La tension entre paysages fermés et ouverts y est d’autant plus forte que la Montagne limousine a subi au cours du XXe siècle une véritable « inversion paysagère » (Périgord, 1993) : les vastes espaces ouverts de moyenne montagne avec les petits troupeaux de brebis gardés par des femmes ou des enfants des cartes postales anciennes ont rapidement été colonisés par la forêt – accrus sur les surfaces délaissés et enrésinement intensif à la faveur du Fond Forestier National. Ce sont ces paysages emblématiques de landes et de tourbières, perçus parfois avec nostalgie (Sans, 2023), que le CEN a pour mission de conserver et de restaurer en développant, notamment, des partenariats avec des éleveurs pour la création d’estives.Dans l’imaginaire collectif, le recul des bois sous la dent des troupeaux est un fait bien établi et dans l’esprit de nombreux forestiers les bêtes dégradent forcément les milieux forestiers. Une compétition entre forêts et pâturages pour le contrôle matériel et symbolique de l'espace va ainsi émailler toute l'histoire contemporaine du plateau de Millevaches. Pourtant, depuis une dizaine d’années, des bergers et leurs brebis s’infiltrent, à l’insu des propriétaires, dans les plantations forestières et les friches ligneuses attenantes aux tourbières où se déroulent les estives. Se produit alors une connexion, dans leurs interstices, entre ces deux mondes antagonistes.À travers l’ambivalence des petits éléments qui composent le paysage – ces « impondérables chargés de significations » du poète Miguel Torga (2008) – il est possible de rendre compte des reconfigurations qui s’opèrent entre forêts et pâturages et de l’institutionnalisation des pratiques cachées des bergers : leur passage dans les mœurs ou la culture locale.La canche flexueuse (Deschampsia flexuosa) est un de ces petits éléments du paysage. Avec cette plante herbacée très présente dans les plantations forestières du plateau se noue un lien étroit et ambiguë entre institutionnel et informel, instituant et institué : l’institutionnel du néo-pastoralisme des estives et du gardiennage pour la gestion des tourbières ; celui aussi de la régénération naturelle des parcelles de résineux gérées par l’ONF et que la présence d’un feutrage dense de canche au sol rend problématique ; l’informel des pratiques de conduite des troupeaux qui nécessitent de faire des incursions dans les bois, à la dérobée, pour créer des relances d’appétit avec la canche flexueuse qui s’y trouve ; enfin, l’instituant des expérimentations de sylvopastoralisme que nous mettons en place (en collaboration avec l’École Forestière de Meymac, L’Association pour le Pastoralisme de la Montagne Limousine, des propriétaires forestiers, l’ONF et le CEN) et qui font naître de nouveaux imaginaires, de nouvelles formes de relations et de pratiques.L’objectif est de rapprocher les mondes de la forêt et de l’élevage en montrant qu’il est possible de conjuguer, avec des pratiques sylvopastorales, gestion forestière (réduction des interventions mécaniques pour les dégagements forestiers, la préparation des sols ou le contrôle de la canche grâce au passage régulier des brebis), gestion pastorale (avec des systèmes agro-pastoraux économes) et gestion écologique (conservation des tourbières, régénération naturelle des peuplement ou enrichissement de la biodiversité des plantations grâce aux insectes coprophages et aux chauves-souris qui les chassent)
Statistical harmonization of versions of measures across studies using external data: Self-rated health and self-rated memory
No full textInternational audiencePURPOSE: Harmonizing variables for constructs measured differently across studies is essential for comparing, combining, and generalizing results. We developed and fielded a brief survey to harmonize Likert and continuous versions of measures for two constructs, self-rated health and self-rated memory, for use in studies of French older adults. METHODS: We recruited 300 participants from a French memory clinic in 2023 to answer both the Likert and continuous versions of self-rated health and self-rated memory questions. For each construct, we predicted responses to the Likert version with multinomial and ordinal logistic models, varying specifications of continuous version responses (linear or spline) and covariate sets (question order, age, sex/gender, and interactions between the continuous version and covariates). We also implemented a percentiles-based crosswalk sensitivity analysis. We compared Cohen's weighted kappa values to identify the best statistical harmonization approach. RESULTS: In the final models [multinomial models with continuous version spline, question order (self-rated memory model only), age, sex/gender, and interactions between the continuous version and covariates], weighted kappa values were 0.61 for self-rated health and 0.60 for self-rated memory, reflecting moderate agreement. CONCLUSIONS: Primary data collection feasibly facilitates statistical harmonization of variables for constructs measured differently across studies
Brainstem serotonin amplifies nociceptive transmission in a mouse model of Parkinson’s disease
No full textInternational audienceAbstract Parkinson’s disease arises from the degeneration of dopaminergic neurons in the substantia nigra pars compacta, leading to motor symptoms such as akinesia, rigidity, and tremor at rest. The non-motor component of Parkinson’s disease includes increased neuropathic pain, the prevalence of which is 4 to 5 times higher than the general rate. By studying a mouse model of Parkinson’s disease induced by 6-hydroxydopamine, we assessed the impact of dopamine depletion on pain modulation. Mice exhibited mechanical hypersensitivity associated with hyperexcitability of neurons in the dorsal horn of the spinal cord (DHSC). Serotonin (5-HT) levels increased in the spinal cord, correlating with reduced tyrosine hydroxylase (TH) immunoreactivity in the nucleus raphe magnus (NRM) and increased excitability of 5-HT neurons. Selective optogenetic inhibition of 5-HT neurons attenuated mechanical hypersensitivity and reduced DHSC hyperexcitability. In addition, the blockade of 5-HT 2A and 5-HT 3 receptors reduced mechanical hypersensitivity. These results reveal, for the first time, that PD-like dopamine depletion triggers spinal-mediated mechanical hypersensitivity, associated with serotonergic hyperactivity in the NRM, opening up new therapeutic avenues for Parkinson’s disease-associated pain targeting the serotonergic systems