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In this study, the morphological properties and micro-roughness of chromium thin film prepared by thermal evaporation technique and confirmed via EDS analysis are examined on different substrates of BK7, Silicon (Si), and glass using atomic force microscope analysis (AFM). Analysis of amplitude parameters, Minkowski functionals, and films' spatial microtexture extracted from AFM analysis showed the difference between glass substrate and the other two (BK7 and Si) substrates for the growth of chromium thin films. In addition, we observed robust signatures of multifractality of the Cr thin films deposited on all substrates we studied. Moreover, we highlight that the Glass substrates displayed the strongest multifractality indicating that such samples present space filling properties distributed over more spatial scales than the samples of BK7 and Si.

International audience; To explain irradiation creep, several mechanisms have been proposed. Some are based on the effect of stress on either nucleation or growth of dislocation loops. To investigate these mechanisms in aluminum we combine in-situ transmission electron microscope irradiation under stress and two simulation approaches (object kinetic Monte-Carlo, molecular dynamics Frenkel pair accumulation). We observe the selectivity of Frank loop variants under electron irradiation and applied stress. When the stress is turned on after loop formation, there is no loop variant selectivity, suggesting the absence of preferential absorption on already formed loops. Object kinetic Monte-Carlo simulations, including the effect of stress on the diffusion of point defects, show no growth rate difference between loop variants. Frenkel pair accumulation simulations exhibit variant selectivity of nucleated loops. This shows that loop selectivity is due to preferential nucleation of well oriented loops under stress and not to differential growth of loops.

International audience; A set of segments in the plane may form a Euclidean TSP tour or a matching, among others. Optimal TSP tours as well as minimum weight perfect matchings have no crossing segments, but several heuristics and approximation algorithms may produce solutions with crossings. To improve such solutions, we can successively apply a flip operation that replaces a pair of crossing segments by non-crossing ones. This paper considers the maximum number D(n) of flips performed on n segments. First, we present reductions relating D(n) for different sets of segments (TSP tours, monochromatic matchings, red-blue matchings, and multigraphs). Second, we show that if all except t points are in convex position, then D(n) = O(tn^2), providing a smooth transition between the convex O(n^2) bound and the general O(n^3) bound. Last, we show that if instead of counting the total number of flips, we only count the number of distinct flips, then the cubic upper bound improves to O(n^8/3).

Resume Au sein de notre service, nous travaillons avec un programme de therapie cognitive comportementale centre sur les processus attentionnels. Les parents et educateurs rapportent les effets positifs de celui-ci sur le comportement des adolescents avec un trouble de l’attention avec hyperactivite (TDAH) mais ses effets sur des processus cognitifs precis n’ont encore jamais ete testes. Cette etude s’interesse a l’impact de ce programme sur le controle de l’impulsivite des adolescents avec un TDAH non traite. Nous avons utilise la tâche de Simon (connue pour generer un conflit entre une reponse automatique et une reponse dirigee vers un but) et interprete les resultats dans le cadre theorique du modele « Activation-suppression ». Ce cadre experimental et theorique nous fournit un outil puissant et precis pour etudier le controle de l’impulsivite en dissociant l’activation et la suppression des actions impulsives, ce qui n’est quasiment jamais realise dans les etudes sur le controle de l’impulsivite. Vingt adolescents avec un TDAH non traite ont suivi le programme pendant 12 semaines et nous avons compare leur performance avant et apres la realisation de ce programme. Les resultats montrent que l’amelioration du controle de l’impulsivite observee en fin de session vient a la fois d’une diminution de la propension a declencher des actions impulsives et d’une augmentation de l’efficacite des processus inhibiteurs. Ce programme pourrait donc se reveler une alternative pertinente a la medication stimulante, en particulier quand les parents sont reticents face a la medication ou quand leurs enfants presentent des effets secondaires trop importants.

CG:SHOP is an annual geometric optimization challenge and the 2022 edition proposed the problem of coloring a certain geometric graph defined by line segments. Surprisingly, the top three teams used the same technique, called conflict optimization. This technique has been introduced in the 2021 edition of the challenge, to solve a coordinated motion planning problem. In this paper, we present the technique in the more general framework of binary constraint satisfaction problems (binary CSP). Then, the top three teams describe their different implementations of the same underlying strategy. We evaluate the performance of those implementations to vertex color not only geometric graphs, but also other types of graphs., Comment: To appear at ACM Journal of Experimental Algorithmics

This paper describes the heuristics used by the Shadoks team for the CG:SHOP 2021 challenge. This year's problem is to coordinate the motion of multiple robots in order to reach their targets without collisions and minimizing the makespan. It is a classical multi agent path finding problem with the specificity that the instances are highly dense in an unbounded grid. Using the heuristics outlined in this paper, our team won first place with the best solution to 202 out of 203 instances and optimal solutions to at least 105 of them. The main ingredients include several different strategies to compute initial solutions coupled with a heuristic called Conflict Optimizer to reduce the makespan of existing solutions., Comment: Journal version to appear on ACM Journal on Algorithmics

The French day hospital program specialized in eating disorders (ED) opened in January 2018. Our study presents preliminary data on clinical profiles of patients with anorexia nervosa (AN). We describe more specifically clinical characteristics of patients with early onset AN and according to their therapeutics orientations. Then, we compare the weight gain of patients managed only in day-patient (DP) treatment with those managed initially inpatient (IP) treatment and relays in DP.Ninety-two patients with AN, aged between 8 and 18 years, were evaluated with several questionnaires (EDI-2, EDE-Q, BSQ, EDS-R, CDI, STAI-Y, VSP-A, EPN-13).Patients with early onset AN, n = 23 (25.3%), presented more restrictive behaviors, less marked dietary symptomatology, a lower degree of clinical perfectionism and a less marked feeling of ineffectiveness than adolescent patients with AN. Regarding the choice of hospitalization modality (DP alone or IP-DP), the only difference highlighted was the severity of patient undernutrition. Among the patients who were treated (IP-DP n = 27 vs DP alone n = 25), the weight evolution after one month and at discharge was favorable for both groups.These preliminary data suggest the effectiveness of DP in the care of AN in children and adolescents.

Problematic physical activity (PPA) is a symptom commonly present in patients suffering from anorexia nervosa (AN). This study aims to refine the clinical description of children with early-onset AN and adolescents with standard-onset AN and associated PPA, in order to better understand their associated features, and to offer them adapted care and physical activity programs. 107 participants treated at the Salvator University Hospital Centre of Marseille for AN were retrospectively evaluated by the Exercise Dependence Scale Revised concerning PPA. Other self-report questionnaires were used to evaluate eating disorder, anxiety and depressive symptoms, quality of life, emotions, sleep, and attention deficit disorder with or without hyperactivity. In the entire sample, the presence of PPA was associated with significantly higher levels of eating disorder (EDI-2: p = 0.001) and body image concerns (p = 0.002), anxiety (STAI-Y-trait: p = 0.013) and depression (p = 0.006), as well as significantly lower psychological well-being (p

In this paper, we present our heuristic solutions to the problems of finding the maximum and minimum area polygons with a given set of vertices. Our solutions are based mostly on two simple algorithmic paradigms: greedy method and local search. The greedy heuristic starts with a simple polygon and adds vertices one by one, according to a weight function. A crucial ingredient to obtain good solutions is the choice of an appropriate weight function that avoids long edges. The local search part consists of moving consecutive vertices to another location in the polygonal chain. We also discuss the different implementation techniques that are necessary to reduce the running time., Second place at CG:SHOP 2019 challenge

This retrospective study investigated, for the first time, sleep characteristics in anorexia nervosa (AN) subtypes and the clinical profile in adolescents, as well as the quality of life (QoL) and emotionality in these patients with poor sleep. The sample included 111 adolescents with AN. First, restrictive AN (ANR) and binge eating/purging AN (ANB/P) groups were compared in terms of self-reported sleep characteristics, sleepiness and chronotype. Second, the clinical profile, QoL, and emotionality of good sleepers (GS) and poor sleepers (PS) were compared. Compared to the ANR group, participants with ANB/P showed significantly greater sleep disturbances and sleepiness, and also a higher preference for an eveningness chronotype. Results also showed a clinical profile significantly more severe in PS than in GS. After adjustment, only the ANB/P subtype and the EDI-2 ineffectiveness subscale remained significantly linked to poor sleep. Moreover, the QoL was lower and emotionality more negative in PS with respect to GS. Findings suggest that subjective sleep disturbances may be used as a clinical marker for AN severity and for ANB/P subtype. Importantly, findings suggest that improving sleep quality in adolescents with AN may help managing their ED and their comorbidities, but also improve their QoL. Level V, descriptive study (evaluation data retrospectively studied).

We consider the maximum (weight) independent set problem in unit disk graphs. The high complexity of the existing polynomial-time approximation schemes motivated the development of faster constant approximation algorithms. In this paper, we present a 2.16-approximation algorithm that runs in O ( n log 2 n ) time and a 2-approximation algorithm that runs in O ( n 2 log n ) time for the unweighted version of the problem. In the weighted version, the running times increase by an O ( log n ) factor. Our algorithms are based on a classic strip decomposition, but we improve over previous algorithms by efficiently using geometric data structures. We also propose a PTAS for the unweighted version.

Resume Le harcelement entre adolescents est un phenomene dont l’ampleur grandit, notamment si l’on considere le harcelement scolaire, mais egalement le cyberharcelement et donc la multiplicite des formes de harcelement via internet et les reseaux sociaux. Les adolescents victimes de harcelement sont plus susceptibles de developper des troubles psychopathologiques et presentent notamment un risque plus eleve de passage a l’acte suicidaire. La plupart des jeunes ont consulte un medecin dans les mois precedents pour divers motifs notamment des troubles somatoformes. Il parait primordial de souligner le role des medecins dans la prevention, le depistage et la prise en charge initiale de ces situations. Malgre l’absence de recommandations en France, tous les medecins en contact avec des adolescents : pediatres, urgentistes, medecins generalistes, pedopsychiatres et medecins scolaires devraient etre sensibilises a la recherche de signes de harcelement chez les adolescents et avoir les elements essentiels pour proposer la prise en charge initiale la plus adaptee. Sur le plan medical, comment pouvons-nous aborder la question du harcelement au cours de nos consultations avec les adolescents ? Qu’en est-il de la prise en charge initiale ?

A set $$S \subset \mathbb {Z}^2$$ of integer points is digital convex if $${{\,\mathrm{conv}\,}}(S) \cap \mathbb {Z}^2 = S$$ , where $${{\,\mathrm{conv}\,}}(S)$$ denotes the convex hull of S. In this paper, we consider the following two problems. The first one is to test whether a given set S of n lattice points is digital convex. If the answer to the first problem is positive, then the second problem is to find a polygon $$P\subset \mathbb {Z}^2$$ with minimum number of edges and whose intersection with the lattice $$P\cap \mathbb {Z}^2$$ is exactly S. We provide linear-time algorithms for these two problems. The algorithm is based on the well-known quickhull algorithm. The time to solve both problems is $$O(n + h \log r) = O(n + n^{1/3} \log r)$$ , where $$h = \min (|{{\,\mathrm{conv}\,}}(S)|, n^{1/3})$$ and r is the diameter of S.

International audience; We investigate the influence of elastic properties of point defects on dislocation climb under stress and irradiation. For this purpose, elastic dipole tensors and diaelastic polarizabilities are evaluated in aluminum for vacancies and self-interstitial atoms in their stable and saddle configurations, using density functional theory calculations. These parameters are introduced in an object kinetic Monte-Carlo code and a continuous diffusion model to estimate the stress dependence of dislocation climb, using a dipole of straight dislocations. We show that both parameters have an influence on absorption of point defects under stress, in agreement with previous analytical models. However, the effect of dipole tensor is found only 5 times larger than polarizability, whereas models predict a factor up to 30. In addition, including polarizability reverses the stress angular dependence when a uniaxial stress is applied orthogonal to the dislocation line, so in general polarizability cannot be ignored for simulations under applied stress. Further comparison with analytical models shows that they give a good description of angular dependence, provided saddle point configuration of point defects is not too anisotropic. For vacancies, which are strongly anisotropic in their saddle configuration, models fail to reproduce quantitatively lattice effects on stress angular dependence observed in simulations. Calculations show that dislocation climb velocity under irradiation is expected to be the highest if the stress is approximately orthogonal to the dislocation line, especially along the Burgers vector, and the lowest if the stress is applied close to the direction with the largest projection on the dislocation line.

Virtual reality is a new technology that can be used to model an environment with which an individual can interact using all five senses. It is notably used in psychiatry for anxiety disorders and addictions, and its use in eating disorders has been growing in recent years. Indeed, virtual reality offers interesting advantages, such as its ability to personalize any environment, which is also more secure and controllable. Recent studies show promising results in the understanding, evaluation, and therapeutic management of eating disorders. The use of avatars in anorexia nervosa allows for a correct assessment of the perceptual (body image distortion) and cognitive-affective (body dissatisfaction) components of the body image disorder in a similar way to conventional methods, but also for a better understanding of them. Moreover, avatars allow the development of innovative therapeutic protocols and are thus used in the context of exposure therapy. The new body swapping protocol, based on a multisensory illusion, offers particularly promising results in the reduction of body image disorder. For bulimia nervosa and binge eating disorder, virtual reality has made it possible to better characterize the triggering mechanisms of binge eating episodes through studies that have observed different responses to food-related environments and stimuli. At the therapeutic level, virtual reality cue exposure therapy has the most empirical support. Its aim is to reduce or eliminate the anxiety and craving felt by a patient in response to exposure to food or other food-related cues by preventing the patient from consuming food, and results show clear reductions in anxiety, craving and binge eating episodes. While all these results seem to indicate a bright future for virtual reality in eating disorders, further studies are needed to validate the positive impact of its use, but also its limitations. Notably, cyber sickness could alter the smooth running of virtual reality therapy sessions by causing nausea and disorientation. Moreover, it is important to verify that a therapeutic protocol does not lose its effectiveness when it is transposed into virtual reality. However, virtual reality seems to be a therapeutic tool that is better accepted by patients, and even better by adolescents, which is very interesting for eating disorders since adolescents are the most affected. Virtual reality could therefore help motivate patients to pursue treatment and reduce the dropout rate while offering good therapeutic results. Thus, studies conducted in recent years have shown that virtual reality is a promising tool in the understanding, assessment and treatment of eating disorders, and future research should confirm this, particularly in the adolescent population.

In the eighteenth century, Portuguese settlers and African slaves came from wooden ships from Mazagão-Morocco, North Africa, to the Amazon, settling on the banks of the Mutuacá-Amapá river, where the village of Nova Mazagão was founded – Nowadays Mazagão Velho village. Archaeological surveys around the village of Mazagão Velho, discovered the presence of ruins of a church of stones, dating to the foundation of the village of Nova Mazagão. In this sense, the discovery constitutes in the few vestiges of the first historical constructions of the occupation of New Mazagan. Thus, the objective of this study consisted in the mineralogical characterization of constructive material, ceramic bricks and mortar used in the construction of the old church. The mineralogical composition was determined by X-ray diffraction measurements, with the help of the database of inorganic compounds and minerals PDF2 of the International Center of Diffraction Data contained in the X'PertHighScore Plus program. The results obtained by the diffractograms revealed the mineral phases of quartz, kaolinite, calcite, ilite, rutile and hematite. The mineral quartz, whose diffraction peaks are the most intense, was present in all the samples, in agreement with the expected, because it is the most abundant and resistant mineral in the tropical soils. Kaolinite and calcite were found only in church mortar, corroborating the fact that lime mortar in the Amazon is very common in colonial period constructions. The illite was observed only in the sample of the floor, while the rutile and the hematite were observed in the floor and brick samples, inferring the possibility of painting in these samples, due to the rutile being used as pigments.

International audience; Humans are commonly motivated towards cooperation and prosociality. In this study, we examined this motivational predisposition in autistic individuals. Using an adaptation of the Cyberball paradigm, we investigated subsequent pro-social behaviour after witnessing social exclusion. Participants witnessed and played a series of Cyberball games, rated their affective state and valued emotional faces with respect to their approachability. Results showed that participants from both groups were aware of the social exclusion. However, while neurotypically developing participants engaged in pro-social behaviour in reaction to the exclusion, autistic participants showed less alterations, in terms of either behaviour or affective state. The current findings suggest a distinct motivational drive and processing of social reward stimuli in autism, which may result in behavioural responses divergent from typical development when engaging in the social world.

Resume Introduction Le sommeil de l’adolescent est caracterise par un retard de phase physiologique frequemment exacerbe par l’utilisation intensive des technologies d’information et de communication. La restriction de sommeil ainsi induite en periode scolaire a des consequences sur la sante physique et psychologique de l’adolescent. D’autre part, la plainte sommeil peut correspondre a un certain nombre de troubles pedopsychiatriques chez l’adolescent. Ainsi lorsque cette plainte s’associe a un absenteisme scolaire, la prise en charge somnologique seule s’avere souvent insuffisante. Afin de comprendre le pourquoi de cette inefficacite, nous avons revu cette problematique selon le point de vue du sommeil et de la pedopsychiatrie, puis souhaite mieux caracteriser le profil de ces adolescents. Methode Pour cela nous avons elabore un « kit de depistage » somnologique et pedopsychiatrique duquel decoule un arbre decisionnel de prise en charge. Ce kit a ete teste sur l’annee 2017 dans le cadre de consultations conjointes au centre du sommeil de Lyon aupres des adolescents consultants pour une plainte de somnolence ou d’insomnie associee a un absenteisme scolaire. Resultats Les resultats preliminaires sur 11 patients, montrent la predominance d’un retard de phase du sommeil ou d’une absence de diagnostic sommeil associe dans plus de 90 % des cas a des difficultes anxiodepressives allant de l’episode depressif caracterise aux situations de refus scolaire anxieux et ses troubles anxieux sous-jacents. Les somatisations sont egalement frequentes. Conclusion Ces premieres donnees semblent confirmer la necessite d’une evaluation pedopsychiatrique afin de prendre en charge les difficultes psychologiques de ces adolescents en parallele de leur plainte sommeil et ainsi de leur offrir les meilleures chances d’amelioration, de rescolarisation et d’insertion sociale.

Pathology of adolescence and young adult, schizophrenia can begin in very rare cases during childhood. Two early clinical forms of the disorder have been identified by epidemiological studies: one beginning at the age of 15; the other around 9 years old; While many questions remain unsanswered about the neurobiological and environmental factors - common or distinct - of these two clinical phenotype, both are related to a profoun and lasting alteration of the neurocognitive development whose origin would clearly go back to infancy or to the antenal period. Here we will present a possible story back of schizophrenia in the light of the latest neuroscientific studies in imagery and genetics from adolescence to antenal period.

Very early onset schizophrenia begins before the age of 13. This form of schizophrenia is particularly difficult to diagnose. The differential diagnosis is difficult because some psychotic signs can be passing or be representative of an anxious or depressive disorder. The differential diagnosis with the autistic spectrum disorder is also complex. Finally, other disorders are associated in the majority of the cases. It is a neurodevelopmental disorder with premature cerebral anomalies engendered by the interaction of genetic factors and environmental factors. There seems be a real continuity between the very early form and the adult form although very early onset schizophrenia is a severe form of the disorder which carries a relatively poor prognosis. Its outcome depends both on early screening, the quality of diagnosis and on the speed of multidisciplinary interventions offered.

The deficit in "interference control" found in children with Attention Deficit Hyperactivity Disorder (ADHD) could be due to two distinct processes, which are not disentangled in most studies: a larger susceptibility to activating prepotent response impulses and a deficit in suppressing them. Here, we investigated the effect of 1/ADHD and 2/ methylphenidate (MPH), on these two components of interference control. We compared interference control between untreated children with ADHD, children with ADHD under MPH, and typically developing children performing a Simon task. The main findings were that 1/ children with ADHD were more susceptible to reacting impulsively and less efficient at suppressing impulsive actions, and 2/ MPH improved the selective inhibition of impulsive actions but did not modify the strength of response impulse. This work provides an example of how pharmacological interventions and selective responses to them can be used to investigate and further our understanding of cognitive processing.

MPH is the more often prescribed stimulant for Attention Deficit Hyperactivity Disorder (ADHD), but it has been estimated that 30% of patients do not adequately respond or cannot tolerate it. Therefore, some other therapies are needed, such as cognitive behavioral therapy. Cognitive behavioral therapy is an intervention proposed over several sessions and aimed at modifying behavior by teaching different techniques that participants can re-use to control their symptoms. In our Institute, we used a program centered on attentional and metacognitive functions. It consists of a series of workshops performed in group at the rate of one workshop of 90minutes per week for 12 weeks. Positive effects on the behavior of adolescents with ADHD have been reported by parents and educators, but the effects of the program on specific cognitive processes have never been precisely investigated.In the present study, we evaluated the impact of the program on impulsive control in adolescents with ADHD who are known to present impaired impulsive control. Impulsive control is required each time there is a conflict between an inappropriate prepotent action and a goal-directed action. At an experimental level, impulsive control can be studied with conflict tasks, such as the Simon reaction time task. Interpreted within the theoretical framework of the so-called « Dual-process activation suppression » (DPAS) model, this task is a powerful conceptual and experimental tool to separately investigate the activation and inhibition of impulsive actions, which is almost never done in studies about impulsive control. Twenty adolescents followed the program and were tested before and at the end of the program by using dynamic analyses of performance associated with DPAS model.The results have shown an improvement of the impulsive control after three months of cognitive behavioral therapy, and this improvement was due to both a decrease of the propensity to trigger impulsive actions and an improvement of inhibitory processes efficiency.This program could be a relevant alternative to the stimulant medication, more particularly when parents are reluctant with medication or when the adolescent suffers from important side effects.

Made available in DSpace on 2021-06-25T12:26:07Z (GMT). No. of bitstreams: 0 Previous issue date: 2020-11-23 Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) Using the main results of the Kuramoto theory of globally coupled phase oscillators combined with methods from probability and generalized function theory in a geometric analysis, we extend Kuramoto's results and obtain a mathematical description of the instantaneous frequency (phase-velocity) distribution. Our result is validated against numerical simulations, and we illustrate it in cases in which the natural frequencies have normal and Beta distributions. In both cases, we vary the coupling strength and compare systematically the distribution of time-averaged frequencies (a known result of Kuramoto theory) to that of instantaneous frequencies, focusing on their qualitative differences near the synchronized frequency and in their tails. For a class of natural frequency distributions with power-law tails, which includes the Cauchy-Lorentz distribution, we analyze the tails of the instantaneous frequency distribution by means of an asymptotic formula obtained from a power-series expansion. Univ Estadual Paulista, Dept Fis, BR-13506900 Rio Claro, SP, Brazil Univ Paris Saclay, Serv Phys Etat Condense, CEA Saclay, CEA,CNRS, F-91191 Gif Sur Yvette, France Computat Sci Res Ctr, Beijing 100193, Peoples R China Sorbonne Univ, Lab Phys Theor Mat Condensee, CNRS, F-75005 Paris, France Univ Estadual Paulista, Dept Fis, BR-13506900 Rio Claro, SP, Brazil FAPESP: 2019/12930-9 CNPq: 301318/2019-0 FAPESP: 2019/14038-6

Virtual reality is a new technology that can be used to model an environment with which an individual can interact using all five senses. It is notably used in psychiatry for anxiety disorders and addictions, and its use in eating disorders has been growing in recent years. Indeed, virtual reality offers interesting advantages, such as its ability to personalize any environment, which is also more secure and controllable. Recent studies show promising results in the understanding, evaluation, and therapeutic management of eating disorders. The use of avatars in anorexia nervosa allows for a correct assessment of the perceptual (body image distortion) and cognitive-affective (body dissatisfaction) components of the body image disorder in a similar way to conventional methods, but also for a better understanding of them. Moreover, avatars allow the development of innovative therapeutic protocols and are thus used in the context of exposure therapy. The new body swapping protocol, based on a multisensory illusion, offers particularly promising results in the reduction of body image disorder. For bulimia nervosa and binge eating disorder, virtual reality has made it possible to better characterize the triggering mechanisms of binge eating episodes through studies that have observed different responses to food-related environments and stimuli. At the therapeutic level, virtual reality cue exposure therapy has the most empirical support. Its aim is to reduce or eliminate the anxiety and craving felt by a patient in response to exposure to food or other food-related cues by preventing the patient from consuming food, and results show clear reductions in anxiety, craving and binge eating episodes. While all these results seem to indicate a bright future for virtual reality in eating disorders, further studies are needed to validate the positive impact of its use, but also its limitations. Notably, cyber sickness could alter the smooth running of virtual reality therapy sessions by causing nausea and disorientation. Moreover, it is important to verify that a therapeutic protocol does not lose its effectiveness when it is transposed into virtual reality. However, virtual reality seems to be a therapeutic tool that is better accepted by patients, and even better by adolescents, which is very interesting for eating disorders since adolescents are the most affected. Virtual reality could therefore help motivate patients to pursue treatment and reduce the dropout rate while offering good therapeutic results. Thus, studies conducted in recent years have shown that virtual reality is a promising tool in the understanding, assessment and treatment of eating disorders, and future research should confirm this, particularly in the adolescent population.

This paper considers the question of how to succinctly approximate a multidimensional convex body by a polytope. Given a convex body $K$ of unit diameter in Euclidean $d$-dimensional space (where $d$ is a constant) and an error parameter $\varepsilon > 0$, the objective is to determine a convex polytope of low combinatorial complexity whose Hausdorff distance from $K$ is at most $\varepsilon$. By combinatorial complexity we mean the total number of faces of all dimensions. Classical constructions by Dudley and Bronshteyn/Ivanov show that $O(1/\varepsilon^{(d-1)/2})$ facets or vertices are possible, respectively, but neither achieves both bounds simultaneously. In this paper, we show that it is possible to construct a polytope with $O(1/\varepsilon^{(d-1)/2})$ combinatorial complexity, which is optimal in the worst case. Our result is based on a new relationship between $\varepsilon$-width caps of a convex body and its polar body. Using this relationship, we are able to obtain a volume-sensitive bound on the number of approximating caps that are "essentially different." We achieve our main result by combining this with a variant of the witness-collector method and a novel variable-thickness layered construction of the economical cap covering., To appear on the SODA 2020 special issue of ACM Transactions on Algorithms. arXiv admin note: text overlap with arXiv:1604.01175

INTRODUCTION Insomnia is considered to be a serious public health issue affecting approximately 10% of adults. Chronic insomnia may increase the risk of health problem, psychological vulnerability and proneness to accidents. Cognitive behavioral therapy for insomnia (CBT-I) is recommended as the first line of treatment. Even though CBT-I is widely considered as an effective therapy, 20 to 30% of patients do not respond to this treatment. Mindfulness therapy, known to reduce rumination and stress, could be an interesting complement to enhance CBT-I. The aim of this study is to evaluate the efficacy of therapy combining mindfulness meditation and CBT-I for the treatment of chronic insomnia. METHODS Thirty-three patients, diagnosed with chronic insomnia, aged 18 to 75 years (51±15 years) were recruited between October 2015 and June 2016 at the Sleep Center of Marseille. The patients were then divided into two groups according to their psychotherapy method: group CBT-I alone (17 patients) or a group therapy combining CBT-I and Mindfulness (16 patients). All participants were given five sessions of standard CBT during eight weeks. The patient-reported outcome measures were sleep onset latency, wake after sleep onset (WASO), total wake time, total sleep time, time in bed, sleep efficiency and number of awakening from sleep diaries before treatment (T0) and six weeks later (T1). Assessments were done using Pittsburgh Sleep quality index (PSQI), Insomnia severity Index (ISI), the Epworth sleepiness scale, the hospital anxiety and depression scale (HAD), the dysfunctional beliefs and attitude about sleep (DBAS-16); further, the use of sleeping pills was also recorded at T0 and T1. RESULTS Out of the 33 participants who began the treatment, 29 completed all sessions and were included in the analyses (4 dropouts in the group CBT-I alone). The data shows that each treatment yielded significant improvements over time in sleep variables from the diary, PSQI, ISI, anxiety (P=0.004), DBAS 16, sleeping pill use and vitality measured by SF36 health survey (P=0.004). Comparing the results of the two therapy groups, the meditation associated to CBT-I shows significantly greater rates of reduction in WASO relative to CBT-I group (P=0.009). CONCLUSIONS This study confirms the beneficial effects of CBT for patients suffering from insomnia on sleep parameters, anxiety symptoms and quality of life. Furthermore, this study suggests, for the first time, that combining CBT and mindfulness is a superior approach compared to that of only conventional CBT-I in improving sleep.

In the polytope membership problem, a convex polytope $K$ in $\mathbb{R}^d$ is given, and the objective is to preprocess $K$ into a data structure so that, given any query point $q \in \mathbb{R}^d$, it is possible to determine efficiently whether $q \in K$. We consider this problem in an approximate setting. Given an approximation parameter $\varepsilon$, the query can be answered either way if the distance from $q$ to $K$'s boundary is at most $\varepsilon$ times $K$'s diameter. We assume that the dimension $d$ is fixed, and $K$ is presented as the intersection of $n$ halfspaces. Previous solutions to approximate polytope membership were based on straightforward applications of classic polytope approximation techniques by Dudley (1974) and Bentley et al. (1982). The former is optimal in the worst-case with respect to space, and the latter is optimal with respect to query time. We present four main results. First, we show how to combine the two above techniques to obtain a simple space-time trade-off. Second, we present an algorithm that dramatically improves this trade-off. In particular, for any constant $\alpha \ge 4$, this data structure achieves query time $O(1/\varepsilon^{(d-1)/\alpha})$ and space roughly $O(1/\varepsilon^{(d-1)(1 - O(\log \alpha)/\alpha)})$. We do not know whether this space bound is tight, but our third result shows that there is a convex body such that our algorithm achieves a space of at least $\Omega( 1/\varepsilon^{(d-1)(1-O(\sqrt{\alpha})/\alpha} )$. Our fourth result shows that it is possible to reduce approximate Euclidean nearest neighbor searching to approximate polytope membership queries. Combined with the above results, this provides significant improvements to the best known space-time trade-offs for approximate nearest neighbor searching in $\mathbb{R}^d$., Comment: Preliminary results of this paper appeared in "Approximate Polytope Membership Queries", in Proc. ACM Sympos. Theory Comput. (STOC), 2011, 579-586 and "Polytope Approximation and the Mahler Volume", in Proc. ACM-SIAM Sympos. Discrete Algorithms (SODA), 2012, 29-42

Background Humour is fundamentally a social phenomenon, occurring frequently in social and playful contexts. The positive affect resulting from an experience of enjoyed humour makes it socially rew ...

Les troubles du comportement alimentaire et le refus scolaire anxieux avec retard de phase du sommeil sont des pathologies associees a des problematiques scolaires tres differentes voire inverses. C’est a travers ces deux prismes que nous developperons l’idee du soin scolaire qui se met en place dans le cadre innovant de l’Espace Mediterraneen de l’Adolescent integrant une unite de l’education nationale au sein du service de pedopsychiatrie de l’adolescent. Ce soin specifique nous semble interessant chez l’adolescent puisqu’il permet un travail en milieu « naturel » de certaines difficultes liees aux differents troubles psychiatriques et nous semble etre une aide a la relance du processus adolescent.

Resume Introduction Le refus scolaire anxieux est apparu avec les lois de Jules Ferry instituant l’obligation scolaire en 1882. Dans les classifications psychiatriques internationales, le refus scolaire anxieux n’apparait pas comme un diagnostic en soi. L’objectif principal de cette etude etait de decrire les troubles psychopathologiques d’adolescents en refus scolaire suivis en hopital de jour. L’objectif secondaire etait de comparer le niveau d’anxiete, d’affects depressifs, d’estime de soi, de solitude, d’attachement aux parents et aux pairs et de qualite de vie de ces adolescents, a celui d’adolescents scolarises. Materiel et methode Le groupe refus scolaire etait compose de 22 patients suivis en l’hopital de jour. Le groupe temoin comprenait 21 adolescents scolarises. Les troubles psychopathologiques ont ete definis grâce au questionnaire semi-dirige d’evaluation diagnostique kiddie-schedule for affective disorders and schizophrenia (KIDDIE-SADS). L’intensite des troubles a ete evaluee par des echelles d’auto-evaluation. Resultats Les principaux diagnostics observes chez les adolescents en refus scolaire etaient la phobie sociale (59 %), l’anxiete de separation (50 %), l’episode depressif caracterise (32 %) et le trouble anxieux generalise (18 %). Par rapport aux adolescents scolarises, les adolescents en refus scolaire presentaient un niveau d’anxiete, d’affects depressifs, un sentiment de solitude significativement plus eleves, une estime de soi et une qualite de vie plus faible. La perception de l’attachement de ces adolescents a leurs meres et a leurs pairs etait plus faible. Conclusion Les adolescents en refus scolaire ont des troubles severes, domines par des profils psychopathologiques varies. Ces difficultes ont un impact sur le sentiment de solitude et la qualite de vie. L’attachement semble jouer un role dans ce trouble.

Resume La prise en charge actuelle du trouble deficit de l’attention/hyperactivite (TDA/H) repose principalement sur la pharmacotherapie. Le methylphenidate est le psychostimulant ayant l’AMM en France chez l’enfant et l’adolescent (mais pas chez l’adulte). Dans le cas d’une reponse incomplete au methylphenidate, de contre-indications, d’une mauvaise tolerance faisant necessiter une diminution des posologies ou un arret du traitement, de refus du traitement ou chez l’adulte, des alternatives therapeutiques doivent etre mises en place. Les alternatives utilisees jusqu’a present, principalement de type education therapeutique et remediation cognitive, ne permettent pas d’atteindre les reponses therapeutiques obtenues par le methylphenidate. Dans ce contexte, les techniques de stimulation cerebrale non invasives ont ete envisagees comme therapeutique du TDA/H. Nous avons realise en fevrier 2016 une recherche des etudes explorant l’utilisation de la stimulation magnetique transcrânienne repetitive (rTMS) et de la transcranial direct current stimulation (tDCS) dans la prise en charge du TDA/H. Les publications ont ete recensees a partir de la base de donnees electronique Pubmed grâce a une equation de recherche associant les termes Medical Subject Headings (Mesh) suivants : « attention-deficit disorder with hyperactivity » et « transcranial magnetic stimulation » pour la rTMS et « attention-deficit disorder with hyperactivity » et « transcranial direct current stimulation » pour la tDCS. Suivant nos criteres d’inclusion, cinq etudes ont ete retenues sur la rTMS et quatre sur le tDCS. La rTMS a ete utilisee avec une efficacite significative dans quatre des cinq etudes. Elle pourrait s’envisager en complement du traitement medicamenteux chez les patients ayant des symptomes persistants ou des alterations cognitives associees ou bien en traitement de deuxieme intention chez ceux presentant une mauvaise tolerance ou une inefficacite des psychostimulants. La tDCS a ete utilisee avec une efficacite significative dans trois des quatre etudes. La tDCS pourrait s’averer utile pour ameliorer les alterations cognitives de certains patients, utilisee seule ou en association avec des techniques de remediation cognitive. Cependant des etudes d’efficacite supplementaires sont necessaires pour asseoir le niveau de preuve de la rTMS et de la tDCS dans le TDA/H ainsi que leurs places dans les strategies therapeutiques actuelles.

Resume Objectifs Le but principal de cette etude etait de verifier si les tres jeunes enfants « a risque » de depression presentent un biais emotionnel negatif qui est une des caracteristiques de cette pathologie. Nous avons egalement evalue les competences de reconnaissance des emotions chez des enfants de 36 mois et leurs liens avec le sommeil. Methodes Cent trente-trois enfants âges de 36 mois, issus de la cohorte AuBE, ont passe une tâche de reconnaissance des emotions faciales de joie, colere et tristesse. Les fonctions cognitives ont ete evaluees par la WPPSI III et differents parametres du sommeil ont ete enregistres via des questionnaires aupres des meres a 6, 12, 18, 24 et 36 mois apres la naissance. Parmi ces enfants, 21 avaient une mere avec au moins un antecedent de depression (13 garcons) et constituent le groupe a haut risque et 19 enfants (8 garcons) nes de meres n’ayant aucun antecedent de depression, le groupe a faible risque de depression (ou groupe controle). Resultats Les enfants de 36 mois reconnaissent significativement mieux la joie que les autres emotions avec une meilleure capacite de reconnaissance globale chez les filles que chez les garcons et une correlation positive entre la capacite de reconnaissance globale et l’indice verbal du quotient intellectuel. On retrouve egalement une correlation negative entre le temps de sommeil a 18 et a 24 mois et la reconnaissance de l’emotion de tristesse, entre les difficultes au coucher a 18 mois et la reconnaissance de la joie et positive entre l’heure du lever a 24 mois et les performances globales de reconnaissance des emotions. Enfin, les garcons du groupe a haut risque reconnaissent selectivement mieux la tristesse que les garcons du groupe controle. Conclusion Cette etude confirme une reconnaissance des differentes emotions liee au developpement et un avantage feminin ainsi qu’un lien avec les capacites langagieres des 36 mois de vie. Nos resultats montrent surtout qu’on retrouve, des ce jeune âge, un lien entre les caracteristiques du sommeil et la capacite de reconnaissance emotionnelle ainsi qu’un biais negatif dans cette reconnaissance emotionnelle chez les garcons a haut risque de depression.