Rôle écologique de la biodiversité intraspécifique en milieu aquatique

Le déclin actuel de la biodiversité a poussé un grand nombre d’études à s’intéresser aux relations entre la biodiversité et le fonctionnement des écosystèmes. La diversité intraspécifique est une facette centrale de la biodiversité qui permet aux espèces de s’adapter aux variations environnementales et dont l’importance écologique est de plus en plus examinée. A l’aide d’une méta-analyse synthétisant des données sur plusieurs espèces et écosystèmes, nous avons démontré qu’un changement de la diversité intraspécifique peut avoir des conséquences écologiques aussi fortes qu’un changement de la diversité spécifique. Ensuite, au travers d’études empiriques nous avons étudié la diversité fonctionnelle et trophique de populations sauvages de vairons (Phoxinus phoxinus), une espèce de poisson abondante en rivière. Une forte variabilité fonctionnelle et trophique a été montrée entre populations de vairons. Cette diversité était structurée de manière complexe du fait de l’action jointe des conditions environnementales, de facteurs évolutifs et des multiples liens existants entre les traits et la niche trophique. Par ailleurs, nous avons montré expérimentalement que les différences fonctionnelles entre populations de vairons pouvaient engendrer des conséquences écologiques aussi fortes qu’une augmentation de la température. De plus, des populations plus diversifiées génétiquement soutenaient des diversités spécifiques élevées puis augmentaient l’intensité des processus écosystémiques. Ces travaux mettent en évidence que la diversité intraspécifique est une composante essentielle de la biodiversité qui doit être considérée comme un facteur majeur affectant la structure des communautés et le fonctionnement des écosystème

La reconnaissance des aidants informels : care, justice et vulnérabilité dans la famille

Doctorat réalisé en cotutelle avec l’Université Paris I- Panthéon Sorbonne.Dans les années 90, le virage ambulatoire a augmenté le maintien à domicile dans une période où, paradoxalement, la population est devenue vieillissante. Même si, cette politique permis une meilleure répartition entre les soins formels et informels, lorsque les familles sont confrontées longtemps à la maladie d’un de leurs membres, l’accroissement de la vulnérabilité des aidants est une conséquence réelle. En raison de la conscience du vieillissement de la population, certains politiciens se sont engagés à faire de l’aide informelle une thématique d’actualité. Cependant, il n’en est rien. Comment exprimer leur vulnérabilité et mettre en évidence qu’elle est un important enjeu de justice sociale ? Telle est la question centrale de cette recherche. Mon but est de montrer comment les politiques de prise en charge de la dépendance ont des conséquences sur les choix privés et, de cette manière, sur l'égalité des chances des aidants. Cette thèse explore la façon dont leur travail devrait être reconnu dans une société juste. Les personnes qui soignent leur enfant ou à un membre de leur famille handicapé ou vieillissant ont moins d’opportunités que ceux qui ne réalisent pas les tâches de soins. Une théorie de la justice adéquate devrait reconnaître ces désavantages comme des injustices. En particulier, elle devrait permettre aux aidants de choisir de soigner une personne dépendante. Cette thèse examine cette question. Dans la première partie, j’explore les enjeux moraux de l’aide informelle dans le but de dépasser les présupposés qui nuisent à la compréhension de cette thématique. La deuxième propose une réflexion politique pour montrer que la question n’est pas seulement enfermée dans la sphère domestique et qu’elle concerne la société. Elle pourrait être résolue autour d’une conciliation entre care et justice. Pourquoi le care devrait-il être le cœur de la justice ? Cette analyse ouvrira à un examen sur notre responsabilité de protéger les personnes vulnérables et à une réflexion sur la dépendance secondaire associée au travail de care.In the 90's, ambulatory transfer increased care-giving at home in a period where paradoxically the population is ageing. Even though, this policy will allow a better distribution between formal and informal care, we must remain cautious on its actual consequences when families are confronted during a long term to a disease of one of its members. One real consequence is that the increased caregivers’ vulnerability. Due to the awareness of the aging population and the need for progress in research on neurodegenerative diseases, some politicians have committed to make of informal caregivers one topic of current interest. However, it is not so. How to express the vulnerability of caregivers and to emphasize that its overcoming represents an important social justice issue? Such is the key issue of this research. My goal is to demonstrate how public policies on dependency have consequences on private choice and by the way on caregiver's opportunity. This dissertation explores the way in which the labor of caregivers would be recognized in a just society. Caregivers who provide care for their own children, a disabled member of their family or older have less income and wealth, lower status, and fewer job opportunities than non-caregivers An adequate theory of justice should recognize these disadvantages as injustices In particular, it should allow caregivers to choose to take care of to a dependent person. I study this question in two parts. In the first section, I explore the moral issues of informal care in order to overcome assumptions that impede a proper understanding of this topic. The second part offers a political thought in order to show that this issue is not only confined to the domestic sphere and it relates to society. It is about reconciliation between care and justice that it could be resolved. Why care should be the heart of justice? This analysis opens a review of our responsibility to protect the vulnerable and questioning the secondary dependence associated with work done with these people

Importance of harvest-driven trait changes for the management of invasive species: letter

International audienceAlthough intraspecific differences between the phenotypes of organisms are an important driver of ecological dynamics (Des Roches et al. 2018), research to help integrate phenotypic variation and its drivers with ecosystem management has been limited. For this reason, the novel conceptual framework proposed by Palkovacs et al. (2018) – which helps to clarify the ecological implications of harvest‐driven trait changes – is timely

Preliminary evidence that fatigue contributes to anhedonia in stable individuals diagnosed with schizophrenia

ObjectivesAnhedonia and fatigue are trans-diagnostic symptoms commonly observed in schizophrenia. Anhedonia is a core negative symptom with a strong relationship with depression and is associated with diminished global functioning. Similarly, fatigue is also associated to depression and research across psychiatric illnesses indicate that fatigue may persist even when primary symptoms are treated. Although fatigue is common in people diagnosed with schizophrenia, it is under studied within this population. The objective of this exploratory study was to investigate the association of fatigue and anhedonia by controlling for depression in a sample of individuals diagnosed with schizophrenia.MethodFifty-one stable individuals diagnosed with schizophrenia from the University Department of Adult Psychiatry in Montpellier took part in this study. Participants completed questionnaires on fatigue impact and depression, and were assessed for symptom severity. Following data collection, statistical analyses were conducted in order to explore associations between clinical variables and fatigue impact. Based on the results obtained, a hierarchical linear regression was conducted in order to investigate whether fatigue impact contributed to the variance of negative symptoms.ResultsThe hierarchical linear regression indicated that when controlling for depression, fatigue impact contributes to ~20% of the variance of anhedonia. Together the social impact of fatigue and depression contribute to 24% of the variation of anhedonia.ConclusionTo the best of our knowledge, this exploratory study is the first to investigate and show that fatigue impact may contribute to anhedonia. We recommend further research to investigate fatigue, its impact on symptomatology, and better categorization of negative symptoms in hopes of developing targeted fatigue treatment interventions

Role of Gaze Cues in Interpersonal Motor Coordination: Towards Higher Affiliation in Human-Robot Interaction

Background The ability to follow one another's gaze plays an important role in our social cognition; especially when we synchronously perform tasks together. We investigate how gaze cues can improve performance in a simple coordination task (i.e., the mirror game), whereby two players mirror each other's hand motions. In this game, each player is either a leader or follower. To study the effect of gaze in a systematic manner, the leader's role is played by a robotic avatar. We contrast two conditions, in which the avatar provides or not explicit gaze cues that indicate the next location of its hand. Specifically, we investigated (a) whether participants are able to exploit these gaze cues to improve their coordination, (b) how gaze cues affect action prediction and temporal coordination, and (c) whether introducing active gaze behavior for avatars makes them more realistic and human-like (from the user point of view). Methodology/Principal Findings 43 subjects participated in 8 trials of the mirror game. Each subject performed the game in the two conditions (with and without gaze cues). In this within-subject study, the order of the conditions was randomized across participants, and subjective assessment of the avatar's realism was assessed by administering a post-hoc questionnaire. When gaze cues were provided, a quantitative assessment of synchrony between participants and the avatar revealed a significant improvement in subject reaction-time (RT). This confirms our hypothesis that gaze cues improve the follower's ability to predict the avatar's action. An analysis of the pattern of frequency across the two players' hand movements reveals that the gaze cues improve the overall temporal coordination across the two players. Finally, analysis of the subjective evaluations from the questionnaires reveals that, in the presence of gaze cues, participants found it not only more human-like/realistic, but also easier to interact with the avatar. Conclusion/Significance This work confirms that people can exploit gaze cues to predict another person's movements and to better coordinate their motions with their partners, even when the partner is a computer-animated avatar. Moreover, this study contributes further evidence that implementing biological features, here task-relevant gaze cues, enable the humanoid robotic avatar to appear more human-like, and thus increase the user's sense of affiliation

Deciphering reward-based decision-making in schizophrenia: a meta-analysis and behavioral modeling of the Iowa Gambling Task

Background: Patients with schizophrenia (SZP) have been reported to exhibit impairments in reward-based decision-making, but results are heterogeneous with multiple potential confounds such as age, intelligence level, clinical symptoms or medication, making it difficult to evaluate the robustness of these impairments. Methods: We conducted a meta-analysis of studies comparing the performance of SZP and healthy controls (HC) in the Iowa Gambling Task (IGT) as well as comprehensive analyses based on subject-level data (n = 303 SZP, n = 188 HC) to investigate reward-based decision-making in SZP. To quantify differences in the influence of individual deck features (immediate gain, gain frequency, net loss) between SZP and HC, we additionally employed a least-squares model. Results: SZP showed statistically significant suboptimal decisions as indicated by disadvantageous deck choices (d from 0.51 to −0.62) and lower net scores (d from −0.35 to −1.03) in a meta-analysis of k = 29 samples (n = 1127 SZP, n = 1149 HC) and these results were confirmed in a complementary subject-level analysis. Moreover, decision-making in SZP was characterized by a relative overweighting of immediate gain and net losses and an underweighting of gain frequency. Moderator analyses revealed that in part, decision-making in the IGT was moderated by intelligence level, medication and general symptom scores. Conclusion: Our results indicate robust impairments in reward-based decision-making in SZP and suggest that decreased cognitive resources, such as working memory, may contribute to these alterations

Influence of facial feedback and mind perception during a cooperative human-robot task in schizophrenia

This is the author accepted manuscript. The final version is available from Springer Nature via the DOI in this record.Rapid progress in the area of humanoid robots offers tremendous possibilities for investigating and improving social competences in people with social deficits, but remains yet unexplored in schizophrenia. In this study, we examined the influence of social feedbacks elicited by a humanoid robot on motor coordination during a human-robot interaction. Twenty-two schizophrenia patients and twenty-two matched healthy controls underwent a collaborative motor synchrony task with the iCub humanoid robot. Results revealed that positive social feedback had a facilitatory effect on motor coordination in the control participants compared to non-social positive feedback. This facilitatory effect was not present in schizophrenia patients, whose social-motor coordination was similarly impaired in social and non-social feedback conditions. Furthermore, patients’ cognitive flexibility impairment and antipsychotic dosing were negatively correlated with patients’ ability to synchronize hand movements with iCub. Overall, our findings reveal that patients have marked difficulties to exploit facial social cues elicited by a humanoid robot to modulate their motor coordination during human-robot interaction, partly accounted for by cognitive deficits and medication. This study opens new perspectives for comprehension of social deficits in this mental disorder.This experiment was supported by a grant from the European Union’s Seventh Framework Program (FP7 ICT 2011 Call 9) under grant agreement n FP7-ICT-600610 ALTEREGO

Unravelling socio-motor biomarkers in schizophrenia

We present novel, low-cost and non-invasive potential diagnostic biomarkers of schizophrenia. They are based on the ‘mirror-game’, a coordination task in which two partners are asked to mimic each other’s hand movements. In particular, we use the patient’s solo movement, recorded in the absence of a partner, and motion recorded during interaction with an artificial agent, a computer avatar or a humanoid robot. In order to discriminate between the patients and controls, we employ statistical learning techniques, which we apply to nonverbal synchrony and neuromotor features derived from the participants’ movement data. The proposed classifier has 93% accuracy and 100% specificity. Our results provide evidence that statistical learning techniques, nonverbal movement coordination and neuromotor characteristics could form the foundation of decision support tools aiding clinicians in cases of diagnostic uncertainty

Phenotypic determinants of inter-individual variability of litter consumption rate in a detritivore population

The metabolic theory of ecology predicts resource consumption rates of animals from their body mass, but other phenotypic traits might affect individual resource consumption rate. In this paper, we used a hierarchical framework to examine relation- ships between phenotypic traits thought to constrain variation in per capita resource consumption rate. Physiological and behavioural traits were assumed to be impor- tant in mediating the control of morphology and sex on consumption. We conducted a longitudinal study aiming to relate the consumption rate of submerged leaf litter to sex, morphological, physiological and behavioural traits in an aquatic detritivore population. Then, we analysed the pattern of trait covariation using structural equa- tion modelling (SEM). We observed broad and repeatable inter-individual variation in leaf consumption rate and other phenotypic traits. We found that expressing litter consumption rate relative to the time individuals spent feeding revealed and increased the effect of body mass and sex differences, respectively. Accordingly, SEM analyses showed that time allocated to resource acquisition mediated body mass and sex effects on apparent litter consumption rate whose variation was also accounted for by an indicator of activity-specific metabolic rate. Substantial variation in resource consump- tion rate was due to sex difference whereas body mass was of secondary importance. Individual phenotypic trait variations strongly altered consumer–resource relation- ships. Therefore, we encourage studies on consumers’ intraspecific variability to advance knowledge about phenotypic determinants of individual resource consump- tion, an important link between individuals and ecosystems